Poppy is not a very good solo top in early game but if your jungler does his job, you will farm enough to be unstoppable mid and end game. With your passive, you have to try to kill somebody diving you. With your stun and the burst of your A with the Sheen, you can make kills and be a good partner for a gank. Don't try to chase so much until the level 11, your damages don't permiss to go so far. When you have the Trinity Force and the Phatom Dancer, use your ulti on a tank which have no control and go in the back of the team fight (the ennemy's side) and burst all the carrys (like Ashe, Cait, Vayne...) They can do nothing against you and you can kill them in 3 or 4 kicks mid game and in 2 or 3 kicks end game..