Greetings, and welcome to the demon jester lair!
My guess is you came here for the guide, so lets get this started shall we.

Having played alot of games in S1 with Shaco with an 80% win watio, with over 2k games in normal and possibly 250 matches and more with this champ I have decided to create this guide, seeing my success with him. This is my first guide so bear with me, any feedback at the end will be much appreciated. Ty

Greater Mark of Desolation and Greater Quintessence of Desolation are a MUST, Shaco is centered around early game ganking, any other option will reduce your dmg heavily and result in a bad midgame. Crit dmg runes are not good, even if they do boost your Deceive they will still leave your autoattacks a luckfactor on crit and reduce your effectiveness in a fast jungle.

Greater Seal of Armor will save you 1 hp pot while jungling (tested), you can go with Greater Seal of Evasion but I do not recommend it unless you'r going with Ninja Tabi but even then your goal isn't to 1vs1 and any other boots are better, so no.
note: Never go with mana runes.

Here's where you can mix it up, you can go with
Greater Glyph of Magic Resist
Greater Glyph of Scaling Magic Resist
Greater Glyph of Scaling Cooldown Reduction
or Greater Glyph of Cooldown Reduction like I do, these combined with 4 ranks in Sorcery will make your Jack In The Box 14.58 sec at lvl 1 instead of the 16sec+, calculate 5 Jack In The Box placed, you just saved yourself 6-7 secs.

21/0/9

Anything else for an AD Jungle Shaco is wrong, why? let me explain:
Your Backstab deals 20% increased dmg add the 5% from Havoc the 31 ar pen combined with your Deceive, you will deal a nice amount of dmg on squishies early game, not to much making you great at taking out bruisers when ganking that nasus,ire,garen,morde whos raping your solo top.

Why 4 points in Sorcery? why 1 point in Archaic Knowledge ? why not that ****ty 4% Alacrity ?

why not? your Two-Shiv Poison deals magic dmg, this will help it, and as I mentioned with your flat cd glyphs this will save you alot of time in early jungling, resulting in faster ganks.

Awareness is a must and 1 point in Utility Mastery and Haste you don't need flash you have your Deceive, ghost with E and red buff will perma slow your oponnent along with help from lanemate you'll secure a kill that much easier.

never take anything in the defense tree. Useless and waste of points.

NOTE: if you want the risky path, check at the bottom of this section.

The 3 work together so I put them in the same chapter.

Start with Cloth Armor and 5 Health Potion, go to the 2 golems place 2 Jack In The Box, now go to red buff place 3 and go smite the big blue wraith, go kill the golems take 2 hp pots take a lvl in Two-Shiv Poison put another Jack In The Box on red buff (4 jitb) and they should do the work for you finish off the small ones, now your lvl 3 take a lvl in Deceive your ready for fb/gank.
tip: Do NOT use your Two-Shiv Poison active at early lvls, it will lose you mana/cost you a gank and for obv reasons because of its passive. (22% chance miss on minions :increases with lvl:)

[i]heres where I see you have several options or ways:[/i]
1. You get fb or your gank worked, now go finish off wraiths buy boots and a ward (place it at enemy red buff)
2. You don't get fb/your gank failed, (you didn't die) go finish off wraiths, you'll have money for boots 1 hp pot left but no ward sadly. Go gank again since your red buff is still on (red buff = you must gank).
3. You don't get fb and you die, your pretty much screwed lol jk, unless your team is good.

After you finish your Wriggle's Lantern, now you need to finish boots. There are 3 good options here all depending on your team as well as enemy team:

Item Sequence:
A. Berserker's Greaves (this must go with trin force for increased MS) if you won't go phantom dancer or try force I suggest you don't buy this item. Go with these boots when enemy has 2 or 3 squishies/small CC/no oracles/you aren't the primary focus target (which you shouldn't be) and your gameplay is centered around bding.

this goes with:
Black Cleaver
Trinity Force
Infinity Edge
Bloodthirster
Banshee's Veil

B. Mercury's Treads, heavy cc? need mr? can't bd? all about the team? this item is for you after this you should get Hexdrinker, will greatly increase your survivability while still offering dmg to them squishies. tip: this item is great when you have great teamplay vs great teamplay, means your being focused the enemy is Sight Ward/ Vision Ward and buying Oracle's Elixir, and they aren't falling for your bd/split push strategy.

this goes with:
Trinity Force
Madred's Bloodrazor
Banshee's Veil
Guardian Angel
Infinity Edge
Elixir of Fortitude (since you sold your Wriggle's Lantern, you dont have lifesteal so red pot is a must anyway late game)

C. Mobility Boots, it's all about the gank with these babies go with phantom dancer and full glass cannon, ward the map and you will decimate any enemy 3 feet away from an ally. Preferably vs non organised teams, or when your team tactic is splitpushing.

this goes with:
Infinity Edge
Last Whisper
Phantom Dancer
Guardian Angel
Bloodthirster

Counter jungling:
*I do not recommend it for inexperienced players, this is very risky/unreliable and can gimp your jungling* nonetheless it is a great tactic.

Here's where you shine.
One of the main reasons everyone hates Shaco is this, wether you go AP or AD you can do it, but this guide is for AD so ill stick to that.
The key to master this part is:
-Know the enemy jungler, their timing their route.
-Key locations to ward
-Is it safe to go for that low hp lee? steal his buff? optimize your timing! check the enemy champs
-Save smite for last hit
-And ofc respawn time for buffs (check at the end in this section)

Alot of junglers start with blue, if they do ignore them, you won't expect a gank from them until their lvl 4, unless in some cases which I will state later on.
Since your route is different and gets you fast lvl 3 for a gank it will be hard to counter you because you will have 3 camps under your control (wraiths,red and golem)

Counter jungling should start at lvl 3-4 after your gank(s) you should get a ward before your wriggles and place it at their red by this time the enemy jungler is going for it, it usually and 90% of times takes only one red buff steal to screw your opponents jungling this will help your team immensely unless it's fiddelsticks, but we'll get to that too.

Do not place a jitb in their jungle at early lvls this will give them an incentive that you are warding or hiding in a brush, instead just 1 ward at red(brush)will be fine

easy to counter jungle champs:

Warwick
No escape mechanism he will most likely go for red at lvl 3-4 which is great for you, when he does and hopefully you have your ward set up, walk up place a jitb autoattackhim, if he
attacks you will win a 1vs1 (remember its you and the lizard attacking him, you have 2 more items )unless for some reason he has exhaust then do not place your jitb until he uses his exhaust (save your deceive to escape via baron route) if he does escape finish the little minions at red buff and if you can't take red (someone is ss or for any other reason) go farm your jungle get madreds razor and an hp pot place a jitb at the end of his red brush so it doesn't trigger but still provides vision, if you can gank DO IT! you just wasted ww time he has to recall and take red to gank, you don't. If not go kill him.

Olaf
Same as warwick even easier since his lifesteal won't do him good vs you until lvl 5, lvl 1-4 hes a free kill in your jungle.

Lee Sin
And only at lvl 3, they all go for that red at lvl 3 he will get 50% hp while red is at 55% hp deceive in while his shield is gone kill him and steal his buff. Nothing more.

Nunu & Willump
Do I need to say anything? no dmg 1 cc, if he gets blue at lvl 1, take his red if possible, prefer to counter him while your red is on. Just in case he has HP quints he can take your dmg call for a gank and you'll get raped by that irelia top because your nasus was busy drooling like a dog "SORRY BRO!"

Fiddlesticks
You don't even need a guide for this kill him at lvl 1,2,3,4 extremely squishy and he can't spam his drain unless it's lvl 2 with blue buff, most fiddles will get blue finish jungle recall then go for red, *try this in custom with a friend let him play fiddle jungle and you shaco get the time when he finishes his route without red, recalls* steal his red (will edit this with an accurate timing but for now this is as good.

Amumu
An amumu with hp quints and ar seals is hard to kill, tho land 1 jitb and he's dead, make sure you have red before and use Q engage, only risk in this is if his team comes to help and or you were spotted coming via wards.

Rammus
Same with mumu tho you have to wait till he uses his Shield, make use of jitb also, don't engage blindly.

PITA (Pain in the ***)

*Only if they are played well*
I will keep this short

Trundle: Slow,as buff,Q(reduces your dmg buffs his), and your dead
Nocturne: W to block, E to fear, Q for steroids do not engage him
Lee Sin: For obvious reasons, ar/lifesteal buff,Q to finish you off,E slows and reveals you
Gangplank: (unless your gonna counter jungle at lvl 1 and 2) {don't}: W counters
yours, his E +Q will **** you up.
Udyr: attack him with red buff on and at 50-70% hp you'll win, if he has red your dead, extremely annoying because of his shield and tiger stance, so I put him in here.


*The Other path*

recommended: Exhaust and Smite
If you want to counter jungle hard, (prefered vs squishie junglers = fiddle lvl 2 after he used drain), or just go for an even faster gank at lvl 2.
Get boots, 1 ward and 1 hp pot, go to red buff place 5 jitb their, kill it and rank 1 in Deceive.

This is based on you getting 100% fb (first blood) to get the money needed to continue jungling and counter jungle, if you'r not sure this will work out don't go for it. Instead stick to the normal route.

Now your support must have CV'ed the blue buff at the start if their jungler was taking it, (if he's not at blue it's the same process, tho you can ward his blue and wolfes)good, go to his red buff quickly (before he goes to wraiths) ward between the lizard and the wraiths so u'll have vision of both, either he will go to the small golem or at wraiths, if he's going golems attack him before he reaches them, if at wraiths wait till he use one of his abilities then jump in. *CARE FOR SS*

Note: Since everyone takes flash these days this may not work vs a decent player, but you'll have him waste flash but you just wasted your time, instead use this method for a fast gank it's guaranteed to work if your solo top/mid has any form of cc, and the enemy is pushing hard.


Summoner's Rift Respawn Time for jungle creeps:
Small creep camp (Golem/Wolf packs) - 1:40
Lizard Buff - 5:00
Golem Buff - 5:00
Dragon - 6:00
Baron - 7:00
Warith - 1:40

Always:

1. the lane the enemy jungler is focusing
2. top lane
3. mid
4. and bot
5. enemy jungler/counter jungling.

By helping mid you will have yet another ganker on your team resulting in 3vs2,3vs1 situations.
Steal the red buff at early game if you can and you just saved your team a good amount of time of not being ganked/fear factor from their jungler.

Shaco unlike the other junglers is not a creep hog, your all about ganking 110%, jungling is just another way for you to get xp,buffs and gold to increase your ganking potential. Some games I gank top,mid,bot each chance I get, others I just focus on 1 lane, and more then once you'll have those games where you simply can not gank (in these games you focus on warding, counter jungling/dragon and buff controll)

If the enemy team has Evelynn/ Twitch, their warding your jungle then it's your job to get an Oracle's Elixir, if not let the support get it and check for Sight Ward around dragon, after you get Wriggle's Lantern, Boots and a B. F. Sword get an Oracle's Elixir as well, you'r hard to kill, and can quickly roam for Sight Ward/ Vision Ward, plus it makes you that much dangerous in the jungle.

I've never kept on jungling after lvl 7+ sure when red and blue are up you can go for them, but if laning phase is over I suggest let your mage and range carry take them for harrasment, which will buy you more time to push lanes and help your team in a 4vs5 (disscussed in a new section check later)

Champs Like shaco are picked for:
A. Their High burst dmg
B. Their insane teamfights
C. To farm and initiate

Ehhhh WRONG! its
D. Total mind ****
You'r a demon jester you are a troll but an epic troll, the kind that makes your team laugh and their team cry. When You play Shaco think of yourself as in a theatre you are the performer,a magician, your magic act? MAKE THEM DISSAPEAR

You ask for a volunteer from the audience while plotting your devious plan, a little girl raises her arm, you cringe as you think of the possibilities, she comes up on stage and you offer a giant baloon in the shape of a giraffe for her, you tell her to climb on it and suddenly shes lifted up in the air, she gets filled with excitment and her face lightens up, waving to her parents from above they stare amazed and wondering how you did that, but little do they know that your plan is underway, as she reaches mid air on top of the crowd the baloon explodes sparkling dust falls and the crowd is no more, leaving the girl on magic dust she floats away forever silent.

This is what you should do to your opponents.
Also
note: Read the next section for this*



Mentally harrass your opponents, meaning you don't have to just play the game, but if you talk in all chat every now and then it will make your opponents break, even if you don't just by having Shaco on your team and scoring kills while being a general pain to the enemy team they will start flaming (they can't help it) so some nice things to do would be if you toy with your opponents like you are being ganked top while pushing they send 3 to get you and you escape say in allchat/ "next time send 5' people get really annoyed especially when your pushing or bding and they can't stop you. So use this to have them focus you or absurdly chase you accross the map insisting on killing you.

Ranged Carries

You want them your team you hate them on their team.
Ever tried reaching that caitlyn behind that sona, who's hiding behind udyr, whose blocked by that thick granite wall *tank* while malzahar is harrassing your team to half hp and forces you to back or fight and then you jump in get kited to infinity and realise your gonna die but it's too late! *BOOM HEADSHOT*

With Shaco you generally want to avoid these kind of situations and you can. Cold wars and staring contests are not your thing because your harrasment just plain out sucks, your not a great teamfighter and since your burst falls off late mid game then you have to compensate in other areas, which may lead to your team losing if they don't play their part which is simple: DON'T FIGHT

Playing with Shaco on your team makes it a 4vs5 in its own, after jungling and laning phase is over your overall strength diminishes, this is where split pushing comes to use, Master Yi might be regarded as #1 pusher and bder, but Shaco is safer and because of this he's somewhat faster.

Among other things this is why I recommend Haste , before you get Trinity Force or Phantom Dancer your incredibly slow (395 MS) without Mobility Boots, meaning if your get caught your dead.

To push a lane your gonna need:
Wriggle's Lantern
Zeal
Jack In The Box
Sight Ward
boots any will do but I prefer Berserker's Greaves
optional Oracle's Elixir

This provides you with:
MS (movement speed)
AS (attack speed)
2 free wards and an extra just in case

Tell your team to back off and not engage, if they do this the enemy team will have to do something:

1. Ignore your pushing which will lead to a loss of their tower/inhibitor.
2. Force a fight under turret, members of both team will die, and have loss of hp, in this case you can either go clean up the rest or continue pushing, depends on the situation but most of the times your team has the advantage simply because you got and tower they don't ;)
3. Send 2 or more people to take care of you. LOL, tell your team to wipe them off and push, while you run away. Problem?
4. Send someone to take care of you, most likely someone with a global ult Teleport or anyone else, here is where your team has the advantage:
Which champs are the worst in teamfighs: Shaco and only, every other champ can be more beneficial to their team if they stick with them, but not this guy.

You see when you choose to push and leave your team you'r actually doing them a favor, they don't lose much but the opposing team will lose alot by sending someone to you.

pushing,splitpushing and bding is what Shaco is all about, since after the jungle you lose your fear factor and mobility, this way you can maintain those and be tremendesly usefull for your team.

Instead of offering little dmg and a bit of utility in teamfight you are much better off pushing and it comes with benefits:

-Allows you to farm.
-Allows your team to layback while you do the work.
-Offers them a chance to make a comeback in game while holding the enemy at bay.
-You act as a bait, this allows you to move the enemy as you please.
-You maintain your mobility and usefulleness throughout the game.
-More control on river,buffs,dragon,baron because of your mobility Jack In The Box sight ward and Oracle's Elixir.

*note: use this tactic after jungling and laning phase till latemid game*
because after you aquire most of your items it is better to teamfight

Unlike your typical assassin who has to deals "Tons of dmg!" to be useful to his team.
Shaco can be useful in many ways (see above section) and still stand his own in a fight, his job is simple and that is: Chaos!

In teamfights:

1.He can burst down the range carry.
2.Shutdown the ap carry Jack In The Box
3.And deal a nice amount of damage with Hallucinate Pre/Post explosion.

November 1, 2011:
As of today Deceive and Jack In The Box got buffed making your early ganks more dangerous and better at teamfights which is perfect! Allowing you to carry out the 3 steps mentioned!

In a teamfight this is what you should generally do.
Lategame, pushing becomes more dangerous it's a 5on5 roam and 1 ace can mean a win for either team and while everyone is fighting for baron control teamfights are much more important and you are required to help your team since you have most if not all of your items.

Every fight needs an initiator after either team initiates, and (your out of sight hopefully) jump in with Deceive at their back rows toss a Jack In The Box in the midst of the fight and strike at their ranged carry, after this you will be immediately focused so make sure to have your Hallucinate up and ready and use it at the right moment and that Banshee's Veil will come in handy. After you have your clone ready you can choose to either use him on the enemy ranged carry for double the dmg or order him to attack the AP carry.

tip: ALT+rightclick to move your clone.

I'll keep this short.


EarlyGame:
1. Ganking.
2. Counterjungling.
3. Jungling.

Mid game:
1. Warding.
1.1 Pushing.
2. Buffs and Dragon control.

Late Game:
1. Backdooring.
2. Warding.
2.1 Teamfights.

Shaco might work well on his own with any team, but to optimize his role it is better to have mixed role in the team, meaning everyone has his role and sticks to it without having the same kind (such has having Akali Talon Shaco on same or just 2 of any kind)
Which is why I find him to work best with a setup that can kite,cc and harrass well while offering some damage early game.

An optimal team would be something like this:
Solo top: Malphite, Gangplank and Singed
Mid: Annie, Ryze
Bot: Alistar and Caitlyn
Jungle: Shaco

Malphite Has a knockup, a slow and some nice damage to dish out with his Ground Slam
make sure to keep his lane back at tower range, and when you come in for a gank if the enemy is just by brush range he is dead.

Gangplank offers a slow, an MS/AD buff can harras with his Parrrley making your ganks much more efficient!

Singed has a slow and knockback, having you on the team allows him to abuse this, how? you come in with red buff slow them and they have no option but to waste their flash because Insanity Potion + Mega Adhesive and Fling with Shaco will have them dead in no time.

Annie has a stun and at lvl 6 she can get a kill on her own with Summon: Tibbers, ganking before lvl 6 with annie mid is awesome, and lvl6+ is insane! you can ensure her lane dominance, get a few kills for her, and have her role through them squishies!

Ryze is great, he is probably the only champ that works with Shaco on any lane.
Has some decent dmg early, can harrass, and Rune Prison works great with your Deceive and Jack In The Box allowing you to "stun lock" an opponent.

note: Since bot is always warded and if your team doesn't have an Oracle's Elixir early game, I find this combo works really well since your opponents will get slightly distracted if they get hit by a knock up, a stun or any form of disable that is when you should go in!
Deceive + Haste

Alistar has two forms of CC, a Heal, and can towerdive what else can you ask for?
This guy will root the enemy in place while you hack and slash at them with your AD carry bot, along with his heal you'r in for a ride, have them bait the enemy into attacking and laugh as they attempt to towerdive.

Caitlyn Has the Safest early harras allowing her to maintain pressure on opponents throughout the laning phase + having Yordle Snap Trap with Alistar bot is so good that will allow for easier ganks and getting your AD carry fed in no time.


I find this comp to be great allowing you to abuse your fear factor and scoring kills/assissts for your team, even if you can't gank (24/7 tower hug) that means your job is working! the enemy is losing XP because they can't afford to die and your team has a free farm while you can go counterjungle and jungle freely.


Enemy Team

If I had to make a list of this it would be something like this:

1. AOE and High Burst Dmg teams
2. Tanky teams
3. Both of them

Having an enemy comp made of this is sure as hell annoying. If the enemy can take down your team really fast or have a push strat in mind they will ruin your farming and force you into early teamfights, while pushing your towers constantly.
For example:
Mid: Vladimir
Top: Galio
Jungle: Udyr
Bot: Pantheon and Blitzcrank

This team is tanky, all of them have some sort of AOE, while all of them being great initiators and able to soak up and deal damage, while being able to tank towers early and take them out.
Winning these kind of game requires your team to ward, deny the enemy farm by zoning them out and playing safe.

Otherwise a Nice comp vs yours would be like this:
Orianna Mid
Akali Solo top
Udyr Jungle
Vayne and Taric Bot is sure as hell annoying

So having this vs your team you'r gonna have a great match, that is if you like 60mins+ matches.

Sky's the limit with Hallucinate
It can be used to dodge,escape,scout, increase your dmg and most importantly wreck havoc when used in the middle of a fight.

Things you can Dodge with Shaco's Hallucinate (basically any form of skill shot,AOE,single target spells who don't have a speed of 22020202020 Parrrley ):

Summon: Tibbers
Requiem
Enchanted Crystal Arrow and Volley
Mystic Shot and Trueshot Barrage
Hemoplague
Ignite/ Malefic Visions/ Toxic Shot/ Noxious Trap and any DOT (only 1 tick, requires great timing)
Call of the Void
Piltover Peacemaker and Ace in the Hole

etc.

Congratulations!
You made it till the end, for this I have a little treat for you, I enjoy music and I find this particular piece amazing and fits well into a haunting Shaco Gameplay

http://www.youtube.com/watch?v=S1CRsEmC5sQ

All critism, arguments and feedback are welcome! Make sure to vote and comment
and +Rep me if I helped you!