Hey first build, been playing for a little while. I have done some true ridiculous damage with this build and i am not savy with making this look good but felt i had to share to if you can dont judge :X

Always go with the Challenging Smite, it gives that damage true bonus that will be a constant addition to your damage after the Essence Reaver procs upon using you ult to initiate. Try to Deceive into the smite before you use your Ulti, that way the first strike from you Deceive will always be affected by Challenging Smite.

Flash is even more essential in my opinion with shaco then most because he has Deceive to already give him that special play ability. I always save flash for the last crucial moment i can, or not use it at all. You can Flash after Deceive to gain some amazing ground if you go through the jungle to catch that runner.

Finish the Warriors Enchantment with at least Tier 1 boots, and then finish boots asap. You will have a bit less MS then most champs but you should be able to outplay most with Deceive so just practice well. Rush that Essence Reaver and as soon as its finish, go have fun!!! Remember to Deceive into your ult so your right next to them and tap them with the smite before you start attacking. At level 7 i melted Maplhite before he could ult away, i did have Red Buff, but i really did not need it. As soon as your ult comes up you should always go for a kill at this point.

Get a Blade of Ruined King, or at least static shiv. Any boost of AS will be greatly enhanced by Essence Reaver and Lethal Tempo, i would suggest getting the BoRK first and then move right into Guinsoos Rage. With those two AS items and the little bit of LS, you can easily bring down the healthiest of enemies. If you end up needing a 6th item, i usually get Static Shiv for the extra damage on hit from Deceive, but if you need just that little bit extra stay. Deaths Dance is a answer to many problems.

Shaco has the best ganking potential in all of the jungling champs out there. That is if you know when to go in when you start going to lane for that nom nom. Tell your team you are coming, and let them know you need them to initiate first, follow up right after any CC or escapes are used if you can. Do not deceive from bushes or from areas usually warded like both sides of mid. Never gank from the middle bushes, DO NOT go near them. Who does not ward those bushes? So always Deceive from another angle, and try not to go where you think a ward would be and jump out of it.

Also your W ability should always be placed in the direction of the tower to which lane you are ganking as you come in with Deceive. Now this can be tricky, but if they dont see you coming and you can put it behind them it limits their escape, and if they dont see it, then you might just get them if they run away. DO NOT use it as an engage or during combat most of the time, try keeping it for when your Q is up and you can use it around you to help the escape if needed.

The two shiv should only be used when they are trying to run away. Its your slow, not hard to under stand, its a click shot slow that can use from Deceive, DO NOT do this. If you need two shiv to catch up, most likely your out of time to get the kill. Try timing it to when they use and escape or have slowed you and your falling behind. Dont just spam it, your auto is worth more.

And for the final little tid bit...always put a box behind you when you start a fight inside jungle. You can kite them back to it if you end up losing and might quickly change the fight. Mainly, put boxes down whenever you think a fight is about to happen, you never know when they might come in handy.