Hey guys I'm B Solo Lane B also known as just Solo, I'm one of the few Shaco challenger players in North America. I started maining Shaco in season 4 when feral flare was broken and kind of fell in love with the champion and his role in the game.
https://gyazo.com/6a33fa361af7443edced9246aa6886db
My peak rank every season was:
S4: Diamond 5
S5/S6: Didn't play b/c school so Platinum 1
S7: Challenger 720 lp (rank 20)
S8: Challenger 846 lp (rank 10)
So how did I go from Diamond 5 to challenger?
I had to truly understand not just the game, but my specific champion and every quirk about him. The intention of this guide is to show the best possible way to build Shaco and how to win games with him.

https://gyazo.com/be2ecbea9ffe1f28792119ce417a6ab3

These runes are unequivocally the best runes you can take as Shaco.
Dark Harvest - This rune allows you to do all of your burst as one collective damage. I believe this rune to be significantly better than execute as you can proc it MANY times in a single fight. This can be from smiting a camp to get an extra proc or from killing a champion.

Sudden Impact - Even though this rune was nerfed, the lethality it gives still makes it significantly better than both Cheap Shot and Taste of Blood

Eyeball Collection- This is the only rune in the Domination tree that can be interchanged with Zombie Ward. I'm a more aggressive Shaco player and thus take this for the increased damage, but Zombie Ward can be incredibly potent as well.

Ravenous Hunter - This rune is incredibly good because it causes ALL ability damage to heal you. This includes the damage your boxes do in the jungle which, after the your first unique kill, will help you sustain.

Celerity - Celerity has incredibly synergy with Shaco as it allows him to catch up to your target much easier and has great synergy with Shaco's core items.

Waterwalking - As Shaco you want to be navigating the map as much as possible and always having the enemy laner's be afraid of you. Waterwalking allows you to traverse the river areas much much quicker which allows for quick rotations and great invades.

The way I play Shaco is to have an impact as early as possible in the game. I believe that one of the best ways to do that is have an efficient build path.

Starting Jungle Items

Hunter's Machete - Shaco is an auto-attack champion so this is the clear choice of Hunter's Talisman

Rejuvenation Bead - This item builds into Shaco's most core item Tiamat and I really suggest taking this over Refillable Potion every game.

First Back

Tiamat - This item is what lets Shaco clear his camps with ease. Sometimes you don't back with 1050 gold in which case you will get Long Sword and Boots

Early-Mid Game

Berserker's Greaves - Shaco has one of the highest base attack speeds in the game so these synergize incredibly well with him. Another perk is Shaco's Two-Shiv Poison applies a passive slow so sticking to enemies that you can't one shot becomes incredibly good with this. NOTE: Buying Boots is better than Dagger because you want to be around the map as much as possible.

Serrated Dirk - Shaco does extremely well with lethality with the AP->AD change on his E. This item is better than Caulfield's Warhammer due to the extra damage.

Mid Game

Duskblade of Draktharr - Even with the 8.6 nerfs, this item is still crucial to the Shaco Special (the 1 shot). With this item, if the enemy adc or mid does NOT have any armor ( Ninja Tabi or Seeker's Armguard) you have the capability of snowballing through killing them.

After Duskblade of Draktharr you want to build Trinity Force
The build path should be:
1. Phage - With Berserker's Greaves, no one can run away from you due to Phage's movement speed increase and Two-Shiv Poison
2. Sheen
3. Stinger
With Duskblade of Draktharr and Trinity Force your damage is INSANE, do NOT be afraid to one shot squishes as most of the time the movement speed boost from Trinity Force will help you escape

End Game

Towards end game you should be around level 14/15 and this is when I recommend to sell Hunter's Machete for a component of any of the following items.

Youmuu's Ghostblade - The movement speed boost this item gives is incredibly with Deceive to travel long distances very fast

Guardian Angel - I think every Shaco main has been at the point where they one shot someone and die in the process. This is usually do to their team not being able to react fast enough and fully initiate the 4v5 after you've assassinated someone. This item allows you to gain a little bit of extra tanky stats and survive longer.

Titanic Hydra - The auto cancels with this will help you one-shot instantly through Ninja Tabi and Guardian Angel if they are the ad or Zhonya's Hourglass if they are AP.

But Solo, why don't you build Infinity Edge or Statikk Shiv and Mobility Boots or even Ravenous Hydra?

While I don't think any of them are necessarily BAD items on Shaco, I just think the one's I recommend to build are better and here's why:

Infinity Edge - The item's that build into this are extremely costly and as a first item, Duskblade of Draktharr provides more burst as the clone can proc it as well.
Another reason is Cloak of Agility provides no INSTANT stats. The item doesn't help you one shot any faster as when you don't have the item. Essentially, you throw 830g down the drain buying that item.

Statikk Shiv - This item has the same downfall that the pre-req item for Infinity Edge, Cloak of Agility has. Every single piece of this item doesn't help Shaco do what he needs to do. Zeal and Dagger are really useless in their component parts for Shaco.

Ravenous Hydra - I actually don't think this item is that bad but, Titanic Hydra has the animation to instantly auto attack reset as well as health. These two things make Titanic Hydra > Ravenous Hydra

Mobility Boots - Box breaks this and with Youmuu's Ghostblade it's really not needed.

Backstab - Do more damage when you hit from behind. This is extremely useful and often determines a kill or not as well as essential for healthy jungle clearing (extra damage procs healing from Hunter's Machete

Deceive - This is Shaco's engage and also disengage tool. It provides a scaling stealth with a small damager modifier as well as okay base damage. This damage is amplified on Backstab

Jack In The Box - Useful for tanking jungle creeps and cutting off escape paths. This helps Shaco get the fast clear that he's known for.

Two-Shiv Poison - Pretty bad early game (actually does less than an auto-attack at level 1) but scales into a threat with lethality and levels in it. This ability has an increased scaling %ad ratio when leveled up.

Hallucinate - This is where Shaco has great outplay potential. This ability takes you completely out of the game for a moment where you can dodge any ability in the game (even Twisted Fate ult). This is extremely useful for switching turret aggro as well as dodging target cc Twisted Fate (gold card) or auto attacks.

Obviously Jack In The Box is the first ability to start and the last one to max because it is essential his first clear, but provides no instant damage

I put 3 points into Deceive rather than maxing Two-Shiv Poison as the 1 point into Deceive build makes getting ganks off almost impossible. I would argue that even two points in q is extremely hard to get ganks off. The result of this is less damage but, the utility trade-off makes it worth.

So BSolo, I know Shaco's abilities, what to max, and what to build but where do I start? Where do I path?

This is one of the most loaded questions I get especially when I'm streaming. This is hugely dependent on the jungle matchup you're against and your laner's matchups as well. I'll be going into specific matchups later but I want to talk about how to generally path.

For this section I will refer to Jack In The Box as just "Box"

VS Junglers you do NOT want to fight lvls 3-5 OR when you lose 2v2's in solo lane:
Top Side

1 Box Red (30s)
1 Box Red (47s)
1 Box slightly outside of raptor range (1:03)
1 Box slightly outside of raptor range (1:20)
1 Box After pulling raptors into previously set boxes (1:43ish)

Clear red buff first with LEASH from top laner -> Deceive over the wall, Backstab two small raptors and then pull to the boxes. Prioritize backstabbing small raptors over big raptor.

With Red buff we have an insane wolf clear as Shaco. We put one box to tank the small wolves and we make SURE it hits the big wolf. As the trap is setting up backstab one of the small wolves -> trap proc -> backstab big -> other small -> first small wolf -> big wolf -> small wolf. Two backstab procs with red buff kills small wolves so this is EXTREMELY efficient because, while you take slightly more damage because you don't kill one wolf or the other first, we actually save 3-5 seconds by doing this.

Clear blue and then gromp as usual with smiting the blue buff.

Clear bot side scuttle.

You're now lvl 4 and you can either look for ganks or counterjungle. If there are no easy ganks look to invade their raptors (save smite for later) and then krugs. Doing all of these camps will give you around 1050 gold which means you can get tiamat without even getting a kill.

Bot Side
1 Box Blue (30s, 47s)
1 Box outside gromp range (1:03)
1 Box slightly outside wolf range (1:20)
1 Box After pulling Gromp into previously set box (1:43ish)
-> Wolves
-> Red
-> Raptors

The same concept for top applies but this time you have to kill raptors without previously set boxes which means you will be slightly lower HP.

After doing raptors you have to think about who the enemy jungler is. If the jungler clears their gromp on first clear like Skarner, who rushes level 6, potentially Kha'Zix, but definitely not junglers like Elise or Lee'Sin who level 3 gank.

If you're against a jungler who doesn't clear gromp on first clear you will do
-> Scuttle
-> Gromp + Drop ward on intersection of blue buff

VS Junglers you DO want to fight or you win 2v2 in solo lane
Top Side
3 Boxes Blue (30s/47s/1:03)
1 Box on Blast Cone (1:20)
Get leash from bot lane
-> Deceive over and hit blast cone
-> clear wolves as stated before except when you do blue, you drop 1 of the boxes to focus small wolves while you focus on Backstab
-> Clear Red buff
-> Invade their Blue
-> If they started top and didn't clear gromp do gromp
-> Scuttle
-> Look for Gank
-> Raptors
After this you mainly want to get a gank for tiamat or if you're desparate for the gold route bottom for your gromp and look for ganks or vision there.

Bot Side
2 Boxes Red (30s, 47s)
1 Box near wolves (1:03)
1 Box Red (1:20)

Ask for leash and clear as follows
-> Red
-> Wolves
-> Blue
-> Invade
If you can't find anything off the invade (kill) then look to take raptors and krugs as you look for a top gank
-> Gromp and clear towards bottom

Example of Perfect Clear from my Stream:
https://clips.twitch.tv/MoistAuspiciousCheddarTakeNRG

So BSolo, why would I pick Shaco when other assassins can do everything he does but with an escape ( Kha'Zix).

1) Insane Burst
Shaco has some of the highest if not THE highest autoattack burst with my build and runes. This damage can literally define a 1 shot which is the most satisfying thing as Shaco.

2) Mindgames
Shaco's Hallucination can give huge outplay potential for example by micromanaging away your clone while you still auto attack.
Shaco's general presence on the map makes your opponents play completely different

3) Uniqueness
While I compare Shaco to Kha'Zix, Shaco has a certain touch about him that is extremely rewarding. I think this is mostly due to the early power spike of Duskblade of Draktharr and him being a champion not many people play.

This is partly why I love Shaco. If you are fed enough your role is to engage EVERY fight with a one shot. This creates a 4v5 and hopefully you are still alive so your team can follow up and get wins.

Jack in the boxx - This is extremely helpful in sieges and in teamfights. Placing these near where you think a fight is going to be can give crucial CC needed to win fights. Something I like to do when playing with an sniper ult ( Xerath Jhin) is place a box on them while they are ulting so they have protection from assassins and tanks.

To recap: You should be initiating every fight UNLESS, the enemy team is too far ahead to the point where your team needs to "soften" them up a little before you go in.