This Shaco guide for the upcoming patch 7.24 will cover build and playstyle and in depth explanations for rune choices.

Pros
Picking Shaco tilts the enemy team
BM with Shaco is really easy
Shaco is a natural split pusher
Early Snowball = easy early win
early game champ for an early game meta

Cons
Shaco can easily be killed if he is caught out without Deceive up
Anything that gives true vision can make it incredibly easy to deal with Shaco
This build is designed to burst, this also means you can get bursted
Playing Shaco effectively requires massive ammounts of game knowledge
You basically have to read the enemy jungler's mind
Must be very good with mind games, the same trick won't work twice (in a row)

Shaco used to be a champion who was feared for being so diverse in options, but with a lot of item changes and the current state of Shaco he really only has one set build to perform well. That being said here is an explanation on the build path.

Starting Items
Hunter's Machete and Refillable Potion
these are your basic items to start with in the jungle. You probably will not need to use both pots in your first clear if done right.

Early Items
Tiamat for early clear speed
Boots cuz - y'know - boots
Skirmisher's Sabre the burn damage it does will pick you up more kills than you think

Core Items
Enchantment: Warrior damage and CDR to have Deceive and Two-Shiv Poison often
Duskblade of Draktharr great synergy with Deceive and Two-Shiv Poison, will be explained more in skill max

Late Items
Get your lethality items and Infinity Edge to pop squishy champs
Black Cleaver, Mortal Reminder/ Lord Dominik's Regards, and Guardian Angel for fighting tanks and surviving burst.
Ravenous Hydra for wave clear and life sustain

Situational Items
Zz'Rot Portal and [titanic hydra]] for more tank and split push

Runes Reforged honestly helped Shaco and Shaco players out a lot. Making it much more rewarding for being a good jungler. Here's my in depth analysis of what runes you take and why

Domination: The tree of assassin's. Encouraging killing since preseason 8

Electrocute: the same thing with a different title. Riot knew how much we loved thunderlord's so they decided to give BETTER SCALING, Shaco has an easy time getting electrocute to proc. One auto, hydra active, and your shiv. pop goes the squishy.
Note: I know some people say Dark Harvest is great on Shaco. On paper it is really great. Theoretically if you get behind you just stay in your jungle and farm for stacks and still do tons of damage late game. Here's where things go wrong, we are in an early game meta which is why tank shaco is not viable anymore which also means a late game shaco isn't that good either. You'd much rather have the consistent and reliable damage that Electrocute provides.

Sudden Impact: you get free lethality and magic pen for using Deceive and damaging them once. This adds on to Shaco's already intense burst from Electrocute

Eyeball Collection: I personally like this rune more than Ghost Poro because it's so much more rewarding to good junglers. You're given AD and AP for denying the enemy of vision by taking out their wards, or by collecting kills/assists from helping lanes or harassing the enemy jungler. This is personally my favorite rune as of right now because if i'm not at 20 stacks I'm encouraged to go out and destroy wards or get kills, and many people feel the same way. This rune gives more incentive to be a good jungler.


Relentless Hunter: More rewarding for getting kills. For a jungler, out of combat movement speed is important and since you get stacks of bounty for each unique takedown you're encouraged to try to help your lanes out more.

Precision: The tree of clutch play, because who doesn't love the rush of 1hp

Triumph: If you didn't already know, this used to be Dangerous Game but in my opinion I feel a much greater impact from this updated rune now. There have been so many times I almost died to ignite or a tower shot but haven't only because I got the kill and Triumph have just enough health to live. This rune is perfect for the all in playstyle of assassin Shaco because it gives him a better chance of getting out of teamfights without a grey screen.
note: you can take Legend: Alacrity as a secondary if you think that triumph isn't making a big impact on you. This helps you get electrocute faster and more auto's between combos.

Coup de Grace: If you didn't already know it's pronounced Coo-day-grah and not coop-day-grace. This move has great synergy with Two-Shiv Poison because it as well has a type of execute damage on it. The lower the health the more damage you do

Before you put my head on a pike about this skill sequence hear me out.
Deceive's invis time goes up by .75 seconds, starting at 1.5 seconds. This is nowhere close enough to get off propper ganks. Pre-rework Shaco had an invis time of 3.5 seconds and did not change, so leveling the current Q two times gives you almost the same amount of gank time by level 5 . Finish this after maxing Two-shiv poinson
Note: The reason you only get two points into Deceive now instead the original three is because buying Mobility Boots makes up for the lesser invis time

Jack In The Box is maxed third because you're not AP, and even if you built abyssal scepter you'd still max this third. Most of the time you'll use this for jg sustain, watching the enemy team and outplays.

Two-Shiv Poison has execute damage that scales with level capping at 8%. The reason you max this first is because having it at level 1 most of the time is useless since it only does 5 base damage. The later ranks do massive amounts of base damage and scale great. The other reason you max this first is for the passive, it helps sustain you in the jg since it reduces monster/minion attack speed (scaling with skill level), this move and Duskblade of Draktharr have great synergy because while this move is off cooldown you slow enemy champs with auto attacks so the 99% slow from duskblade plus E passive makes for an insane slow that the enemy champ will hate.

Hallucinate okay so why on earth would you not level this at 11 and 16? Simple, the clone will still do the same damage with Basic Attacks, what scales is the explosion and mini box damage and since you're not ap you don't have to worry about those things.

Every time you do camp make sure you use Jack In The Box to draw agro from you and deal more damagem and make sure to always backstab since you get off more damage that way.

After a gank, tax. Even if you got the kill. Is it a jerk move? Yes, but worry about yourself, assassin's like to solo carry. With that being said, don't take an entire wave just a few creeps or one cannon. If you're behind it's better to not tax because at that point it's better to try and just help anyone who can potentially carry you.

Also after a gank go to counter jungle, because if the enemy jg didn't come up to help it means they're one or more of the following: low, opposite jg side, back at base, coming from base, or they're a jerk. You can also use this chance to kill them.

Clearing with Shaco: You always want to backstab since it was optimize your clear speed. Use boxes to clear camps, this as well gives you faster clears and more sustain since they draw agro. Never Deceive into a camp, this is because if you're caught off guard by an enemy champ you can slip away.

Do your best to get out of base as fast as you can. Head to red side and place a Jack In The Box in the river bush ASAP

Put three boxes down at red, one of which far enough away that it wont trigger. After the first two boxes die draw the red buff to the third box, this makes sure you take little to no damage.

If you suspect a possible invade go to your blue next, if not clear your wolves. You probably won't need to smite but you may have to chug a pot.

If you cleared blue go to gromp and smite it and take the camp, then wolves and chug a pot. If you cleared wolves second go to blue to smite and kill, then go to gromp.

Get your scuttle then look to either gank or take enemy krugs.

I personally don't like ganking from bushes since they're almost always warded. Try to Deceive over a wall instead. Get behind the champ you're trying to kill and place a box behind far enough that if they run it'll fear them, they'll usually be forced burn flash or die.

It isn't mandatory to to Deceive in, you can save it in case the one you're trying to kill has their own gap closer. Always Two-Shiv Poison last in your combo since it does execute damage. Use R to dodge damage or CC.