I don't like Rylai's on her. It's not really necessary. I prefer starting dark seal so if you do get kills you get some early damage. If you're vs someone who's going to counterbuild you easily(maw for instance), go AD, rush a trinity force if you can kill him with it, or a sunfire(if he's building maw he's building AD) if you don't think you can. If you went Trinity Force first, sunfire, gunblade, GA, and then maybe some AP. If not, trinity force next, then finish it out similarly. If you're against someone you know ISN'T going to make your damage completely useless, I like to build lich bane, sorc shoes, gunblade, and then whatever I need from then on. When building trinity force start with phage btw. Basically a tanky build if they start building defensively right off the bat(your E does physical damage and the auto from E also helps amazingly with trinity force and lich bane), and a bursty build if they don't. If you know you can get some kills before they start building defensively you should be okay, but in matchups where you know they're gonna be able to easily counterbuild, go AD/defensive so you're not useless. If they have stronger damage than you abyssal if they're AP.