Hi, I'm Maynard and this is the first time I'm making a guide.
I've been playing League of Legends since season 5 but did NOT play ranked until season 8 (February 2018). I am Shaco OTP (one trick pony) and I've climbed with him from Silver 5 to Platinum in just this season alone.

OP.GG: http://euw.op.gg/summoner/userName=sweetchillimayo

I also stream on twitch:
https://www.twitch.tv/sweetchillimayo

So, before we even get to Shaco, you need a few essential jungle skills you want to refine. As a jungler, most of these things should be a habit rather than something that you should be thinking about.

• Minimap - Small but is THE MOST IMPORTANT THING!!! Your eyes should be pretty much glued to the minimap. This way you can pretty much always tell what is going on in the map and you can predict where the enemy jungler is.
  
• Creep Score (CS) - This is the most essential thing in League. YOU SHOULD ALWAYS FARM IF YOU ARE NOT GANKING. I can't stress this enough and also in the jungle, you should always count not just your CS but also the ENEMY JUNGLER's CS. Why? Because it tells you where they've been and that gives you the flexibility to predict where they are going to go next and make decisions from there.
  
• Ganking - Applies to all junglers. For Shaco (and also my playstyle) I will NEVER EVER gank unless I get a kill or assist out of it. Getting flash or any other summoner spells is ok but your laner should be able to bait those out even before you gank.
  
• Mindset - YOU WILL GET FLAMED! Always keep that in your head. Your team will flame you if they are inting and say things like "Enemy jungle has ganked x times, Better jungler wins"... They're just looking for somebody to blame because they do not know what else to do. So you can either mute them OR literally just ignore them. You should never help a losing lane because it will just put your team even more behind. Instead, focus on helping the other lanes and farm up.
  
  In addition, always focus on objectives as well. Don't chase a 30hp Champion which could be bait. Instead secure Drakes/ RIft Herald/ Towers/ Baron. With Shaco's Ultimate, you can do all of these things without your team.

Early Game

I always start on the TOP side of the jungle no matter where I spawn. I will take my top side buff with 4 boxes in a diamond shape. The last box should always be placed right after the buff spawns. This ensures a healthier clear as the buff gets feared twice.
At the same time, because you do not need a leash, your team should not be behind in exp.
You can normally tell where the enemy jungle has started because they will most likely get a leash from their team.
If enemy top side is missing, that means enemy jungler has started top side. If enemy bot is missing, then jungler has started bot side.

With this information, if the enemy jungler started bot side, 80% of the time I will go to the enemy jungler's top side buff. Before I clear the buff, I use Oracle's Lens to see if they have any wards nearby.

If they see you counter jungling, you might get collapsed on OR the enemy jungler might counter jungle you as well.

After this, it is pretty much a race to level 3. With Shaco you can still get to level 3 in under 3 mins. So you can either gank OR just farm some more. Secure your own jungle after you have counter jungled and from that point, gank when your jungle camps are not up.

Finally, the Ideal first back should be when you have at the very least, 1050g. This ensures that you can get tiamat.

Mid Game to Late Game

This is basically when you get your Duskblade. Do what you have been doing (Farm up and gank when needed) only difference is that you deal more damage now.
In terms of Team Fights. Focus the most squishy ones (ADC, Mid and some supports) and your team can clean up easily.
Just don't jump in when enemy is using Oracle Lens.

This is going to be short but sweet.

Shaco's kit makes him very versatile. Play him a lot and learn what you can but the essentials are:

(W) Box Placement
You have to make sure you put the box directly on the enemy's escape path. This means that is you are fighting and he tries to escape, he will then be directly feared and right there is a free kill for you.

Ultimate
Shaco's ultimate is B E A U T I F U L. You and your clone can pretty much do anything without needing the help of your own team. It is extremely useful in taking objectives, engaging OR confusing the enemy team.
One final thing about Shaco's ultimate is the fact that YOU DISSAPEAR OFF THE MAP for like half a second. This basically means that you can dodge MOST abilities in the game (even a Garen Ultimate). You just have to make sure you time it correctly.

This is a short guide but as a shaco main, it is less about the champion but more on the Player's mindset instead. You need to make the right decisions and you need to be thinking and planning based on what's happening on the map.

I hope you found this useful, Please comment and I'll answer any questions you have. I stream most days of the week, so if you can catch me streaming ask me for combos, q jumps and other tips and tricks as well (it is easier to show you than to just try to explain it)

Patch 8.21

- Updated item set. Read Notes.