Farming is hard if you play tristana in the early game so you need to make sure to last hit very carefully,but once you get B.F. Sword then your farming is a lot easier.

Whatever happens don't leap(W) at your opponents in team fights ,let the front liners go in ,and if you don't have front liner because he/she is dead, then don't go in until they respawn.

Also if the enemy team has a lot of stuns ,I suggest not taking runnan's hurricane and take mercurial scimitar.