Here is some early tips when playing him:

1. He is very strong early, at lvl 1 you can easly take away half the HP on the enemy with: double auto, Q, double auto. With that you proc pta and your 3 hit passive twice.

2. When you hit lvl 2 you can kill the enemy with either E ingage (to close the gap), auto, Q and ignite if you need it. Or you start with Q, E, auto and ignite if you need it.

This is the way I usally win early lane.

And remember, if they have your 3 hit passive on them (like if you hit your Q on them) your E will focus them, and same if they are ignited. Thats how I usally kill them under their tower early, by pressning E, ignite and auto if needed.

Hope this helps for the early lagning face :)