Hello! I am Sir Loins, a fairly new league player, it's been about a year now. Honestly, I'm Bronze II (Woo go Bronzie scrubs!) and still learning a lot about this game. However, Thresh is my favorite support and I play him all the time. Eventually I thought, why be a support with Thresh, when he has so much more potential. He can do massive amounts of damage, win solo lanes, and give your team amazing CC. As soon as I started playing him top, I knew that AD Thresh was going to make a comeback. So follow this guide if you want a really fun, tanky assassin. I will be keeping this guide up-to-date as I play him top more often.

Pros
Strong early game
Good poke
Hard hitter
Great CC
Easy to gank his lane
Strong late game
Easy to farm with

Cons
Relatively squishy start
No Escape
Sometimes your team flames
Weak mid game
Can't take towers very fast
Not the best wave-clear
Can be shut down easily
Bad against Champions with sustain

Flay's passive makes Thresh really easy to farm with. His autos are also super smooth so if you're bad at farming, Thresh is good to practice with. Most of the time, in order to get maximum damage off of Flay's passive, you should wait until your minions almost kill the enemy minions, then auto to proc the passive. If you don't hit a minion for a while and the passives damage is full, poke the enemy top-laner instead.

Additionally, try to freeze lane close to your tower. This makes it even harder for your lane opponent to farm because of your constant pressure. Land a hook and Flay if they try to attack you near your turret. If they turret dive you, it doesn't matter how tanky they are, land all of your moves, and they won't be able to touch you.

While laning, stay lose to the river but MAKE SURE YOU HAVE IT WARDED. This makes your lane opponent comfortable with you there; therefore, when your jungler comes in to gank, you can toss out your W to them, and pull in your opponent for a surprise 2v1. If the enemy jungler has a good gap closer, this might not work as well, but as long as you constantly check the map for enemies, you'll get away fine.

When in team fights, you are still engage (unless you have another engage champion on your team). Land a pull, Flay, and ult, then back off. Once your team goes in, shield your assassin with W providing them with a shield and an escape in case their dive goes wrong. If they can't finish off the other team's carry, walk in, auto once, and I guarantee he/she will die. Then just keep using your CC on their carry's to prevent them from wiping out your team.

If you are carrying, then do all of the above statement, and auto the heck out of their team while watching your position to avoid CC. Remember that you have no escapes; so don't run in and kill yourself.