I am Tony Hook,EuWest,And i got 500 games with Thresh between normals and ranked games i got a 55% win rate with Thresh in ranked.And now i am in Gold 2.If someone want to add me my nick name is : RBN Tony Hook

There are some combos with thresh:
You can start flay to slow the enemy and then catch him
If the enemy is a tristana or corki you should start q and then e to stop w's corki or trist.
When u are six u can use flay,then r and finally the q for be sure to not fail it
AND HERE IS THE MOST IMPORTANT THING ON THRESH,THIS IS THE DIFFERENCE BETWEEN A GOOD AND A BAD THRESH:
When u are tying to land a hook u need to imagine that u are the other player and how would you dodge it,so use the hook when u think that u will try to dodge it,most of players try to dodge the hook at the same way always so if u see that he try to dodge it going for the right he probably he will do it again

Thresh have got a good cc kit,but it deppends on the skill of the player,so you can fail all in a tf and u could be useless if u don't hit hooks or flays