This is my way of playing shaco and how I find it works best. I offer a lot of things to swap around for different styles of playing so please read the writing before just down voting to my build
Remember: This is how I play shaco... and this is my first guide so I might of left some things out.

NOTE: This is a guide that was made after the nerf shacos Jack in the boxes got in the Sejuani patch.

Play Video
This is a lucky video i found with the route i roughly use.
Taking Wraiths and Red: At 30 second mark (until minions spawn) Place a Jack In The Box outside of red buff camp, then one outside wraiths, Smite the blue wraith and finish the camp, then place another Jack In The Box outside red and take the camp NOTE: Use two potions during red buff.

Taking Blue: Two Jack In The Box outside of the camp, smite, when the fear has been set off and the JiTB's are attacking, Deceive behind for a crit and quickly finish the camp.

So to recap:

Wraiths >Red Buff >2 potions >2 jacks at blue buff >Smite and kill blue.




After gaining the two buffs, you will be level 3 before anyone else, take this chance to gank, i would usually go to mid first, but see whatever lane works best

NOTE: Dont travel to the furthest lane, Ex: If you come out of blue camp, if you are on the blue team gank top and mid, If on the purple team gank bot and mid.

Stay in the bush and have your team mates set up a gank for you,
Deceive out, Place a Jack In The Box behind your target to block there escape, Land your critical from Deceive FROM BEHIND!, basic attack once and then throw your Two-Shiv Poison, chase them but dont turret dive, if it was a good set up there would be no need for a long chase though.

--Jungling--
Pros:
Good ganking
Fast clear time
High damage output
Scary clown
VERY slippery and can get out of a lot of situations


Cons:
Squishy
Slightly hard to learn



--Laning--
Pros
Slippery
Good burst damage
offensive
fun to play

Cons
Squishy
hard to learn
team mates sometimes get annoyed if your not doing something right or their way... (ignore this though)

Make the most of his passive, do as much of the damage as you can from behind.
JiTB's work against turrets too
JiTB's make good warding for quick lane pushing
Juke people with deceive, whenever possible run backwards or to a side
Make use of your Wriggles ward
Avoid being focused if you can
I personally find mid ganks are best when there is a mage in mid

I chose these runes because they are wide with a lot of characters and also work with a jungle shaco, If you did not want to use these you could alternatively use

Marks: Dont change these...
Seals: Armour over AS
Glyhps: A alternative AD set could be used but i would actually use the flat AP runes anyway.
Quints: These can be used as HP quints if you can't handle his squishiness... but there isn't a lot that you can use to actually be productive...

Smite you need without a doubt... YOUR A JUNGLER
Exhaust: Great to slow, or weaken people, especially in early game ganks
Flash: Can be used but deceive works even better, so not a essential...
Ignite: If you find people are JUST getting away in situations that ignite can seal the deal, by all means take ignite.
Ghost: Suppose it could be used but i wouldn't recommend it unless you really wanted to...

Thought I would talk about my items here...

Wriggle's Lantern you need being a jungler, but also its a great early item for shaco giving him armour, damage and life steal. Make use of the ward it gives you and remember that the can also procs on his ultimate.

Mobility Boots Well i find these the best because you will be ganking a lot and shaco works well with high movement speed, but i suppose you could take Berserker's Greaves if you wanted more attack speed desperately...

Black Cleaver GREAT item early on, high damage and good attack speed...

Zeal I get zeal for some AS before getting Banshees Veil, uhh not much to change around here though as its made into a Phantom Dancer

Banshees Veil Great item to avoid late game squishiness, the passive lets you destroy burst mages (because with one of there moves failing, they can't really execute the kill), It has some MR which i guess is a bonus, HP obviously gives a bit more stability, and the mana again...

Phantom Dancer Buying the first one (from the Zeal you already have is a must, the second Phantom Dancer, however can be exchanged for some more damage like...say a Infinity Edge... I HAVE seen once someone use a Madred's Bloodrazor, but that was because he was vsing people WITHOUT a lot of MR and they DID have high HP. Generally I would only ever buy a Phantom Dancer or Infinity Edge if i needed it.

Overall I find the first items work well but the final item is a luxury item, whatever you like really.

(hell i have gotten a Thornmail to with stand a AD team, totally worked)

A lot of people would think im weird, being a jungler and maxing his Jack In The Box last... WELL i USED TO max it first but i find it works so much better with Two-Shiv Poison and Deceive up first, as they are AD abilities. Also you can jungle without the Jack In The Box being higher...

Two-Shiv Poison Remember these things, it does significantly higher damage if it hits them from behind, also your basic attacks slow the target IF ITS NOT ON COOL DOWN. Remember that...

Deceive Works like flash but with a stealth, but remember these things...
- The orange puff of smoke can be seen anywhere, in the brush or even in the fog of war, so people may run away if they see it while your ganking....
- ALWAYS crit from the back as it deals SO much more damage.

Jack In The Box Place this behind people to cut off a simple escape path, Use it for warding, however, as AD it isn't effective to stack them in a bush, even more so as he can now only leave them out for 60 seconds.

Hallucinate is a unique ultimate.

Tips on how to use it:
-Send it in to take burst damage, then Deceive and commence your burst.
-Lure people to you and your team
-Good farming tool
-Take damage from baron/dragon/Red buff/Blue buff
-When in a fight with someone and your about to lose, ulti and take them out

REMEMBER: If your carrying a buff (baron/red/blue) it only shows on the real you, meaning you can tell the difference

NOTE: To control your ultimate hold ctrl and then right click, this may be a bit buggy if you keep clicking (the real you may run in there)

When laning, it can be a bit harder for some but easier for others.

Before entering the lane, take the blue buff if there is no jungler on your team, this will let you spam moves and gives you a lvl head start. IF there IS a jungler on your team, leave the buff out. If there is a jungler on the OPPOSING team, take their red buff (assuming that they start at blue)

NOTE: when counter ganking leave 1 minion so that the camp has a longer respawn time

Harrasment: To harass you can spam your Two-Shiv Poison, or to really do some damage, Deceive behind them, land your crit, attack once then throw your Two-Shiv Poison. Chase if you think that you can kill them.

REMEMBER: You can do the most damage from behind so make sure you attack from there before the front