Well, he's hard fucked by anything with gapclosers or otherwise ways to disable his stars easily.
So you really can't do anything about that.
Your ultimate works as peel, but it's better to use that offensively.
Start Corrupting/W and W poke harass at level 1 is probably one of the strongest level 1 harasses in the game since most champions don't level up their gapcloser at level 1 and it's easy to deny farm with it as long as you manage your mana usage.
W-Q-E, max W-Q-E.
R whenever possible obviously.
You can greatly increase your damage from your passive by moving clockwise around the target. This is due to the Doppler Effect basically being applied here.
Core item is Rylai's because his stars perma apply it.
RoA is also good for somewhat of survivability + stat ball in general.
Boots should generally be Swifty's outside particular team matchups.
Going GLP-800 instead of RoA's is something I've seen done too, and it can work well, because it still has basically RoA's main passive, but the slow + damage on the active can be really useful for both peels and escapes.
After that, it's just standard items (Rabdon's/Zhonya's if needed/Magic Pen/etc)