Well this is my first build so far so I don't rly know what to say and add so i'll try to explain why i pick that stuff up there. Also my home langue ain't english so i hope you understand what i say:D This isn't perfect build, but for me it have worked just fine, usualy got more kills than deaths.

Pros
-Fun to play as.
-Easy to escape WITHOUT flash
-At mid and late game good ganker and damage dealer.
-Slowing hits, good when chasing.

-Cons
-Low amount of hp
-Some items on build expensive
-Can't stay long on team fights

Feel free to pick other runes you like more if thous doesnt fit your style. Runes doesn't matter alot on this build and you can choose them with free will.

I use shaco as bully, I hit and I run. If you get ganked use decive to teleport over wall, jack to make short time fear or thwor shiv to their fastest player to buy some time for decive. You can also act like your weak to make other attack more aggresive, use decive to teleport on his back, use spells and finish him off. Also nice champ to fool tower divers as you can let them hit once to get turret target them and use decive to let turret deal damage for you.

I use shaco alot as ganker or liner so i don't use points to get longer lasting buffs and spell penetrate to boost abit jacks and to make poison shiv and hallusinate more powerful. Other masterias to simply boost power.

I pick decive first as in early game it's just wonderful escape skill (won't change at mid and late game eighter) and also nice chase skill to get into shiv throw range. Poison Shiv second for slow downs and throwing daggers at opponent on same line to keep them busy. Personaly I never liked of Jack In The Box, for me its kinda usless. Most of time i use it just to escape if decive loading or to help friends to escape as it makes fear. It's good as map vision also, making easier to escape gank. Hallusinate got use for alot of stuff. You can use it to get tower down faster, use it after decive to make it target instead of you when attacking, tower dive with splash surprise and the list goes on.

Reason why I pick items both ad and ap is becouse at shaco i noticed its good to have both. Poison shiv gets bonus damage from both, hallusination makes more damage with ap and decive needs ad. I dont want to make Shaco into mage or carry, more like sneaky killer that picks up lonely easy targets or helps on team fights with fast, short damage deals.
Also im not saying you always need to buy items in this order. Use logic, if alot of stun and that kinda stuff buy Mercury's Tread, if alot of mage delt to you, get mage resist faster and so on.

If someone wants to try this build i would be more than happy to get feedback how it worked. It's kinda hard build so please dont downrate if it wont work perfectly at first try.
I won 4 out of 5 with minium of 5 kills and 9 supports. Death rate was about 2 per game.