Bronze player (let's hope only for this season).
Right now I have around 67% wr on this build and runes.
I play on Eune (please help).

Try to poke your enemy while colleting the souls to your passive, that's pretty much it. Try to push ganking enemies with your e. You can try going in at lvl 2 while having a strong early game adc. In my opinion lvl 8 is good enough to try diving under enemy towers.

Try a little roaming, go into enemies backs, throw a lantern towards the laner and cc the enemy for a free kill. Never go solo into them and watch out for assasins which can still pretty easily get you.

This is the point where Tresh kinda falls off. His only usefull parts are now his W and his Q which both let him support the teammates while not taking that much risk.

1. Be prepared to seeing your teammates use flash instead of your lantern
2. Lantern also gives armor upon walking on it, remember this and use it in mid-fights
3. Your R not only slows but also deals dmg, while fighting in a close 1v1 you can try running away and using it, sometimes it may kill the oponent itself
4. Sometimes you have to take a risk, you can always try to cc the enemy and hide in the bush while hoping that your adc can take the enemy themselfs
5. Try to predict your q instead of tossing it at an opponent
6. Before re-using your q wait a little to drag the enemy towards yourself