First of all if you are against Caitlyn the stuff i will say are really really hard to become.
As Draven you have to focus on farm and one hit trades with the opponent adc if the enemy support isnt janna or something with shield/heal then its easy to trade your opponent just play your skills,no seriusly e-w-q and just hit him 2-3 times.



*Buy wards/pinks B O Y S :D

In mid game you are really strong IF you have took 2-3 kills your passive makes you a beast you allready have at least 3 items(including boots) and you can kill almost anyone just dont overextend





*Wards are almost free 75g is nothing for DRAAAAAVEN :D

You are still strong but not as much as before now you need a good peel probablly by your support and even more good posittion by yourself.