I typically play bruiser besides her so i always end up building her quite tanky.
or
depending on if i jungle her or play her midlane. The cdr is invaluable to me but i usually don't need more than 30%
Always these two and zhonyas should be finished by the time teamfights starts if you need to initiate.
I build this i they have aoe magic damage or their ap focuses me. If I don't get this i get 
As a last item since it gives the extra tankiness and the slows is godly for catch and better initiation.
As for boots typically sorc shoes but i tend to build tabi or merc from time to time too. So yeah not optimal but it fits my playstyle and helps me not getting blown up when i rush in like a retard.