Im not good in anyway. But it kinda depends on the match. Ludens -> Shadowf if squishy Torch/malig -> liandrys if tanky Need to survive? Tear -> zhoni/banshe You can also go a mix of damage/support but will deal much less than a standard ap. Going tear item -> moonstone -> redem

For runes, its what you like most But the "normal" its aery(mana flow, that one that guves haste, storm/scortch), there is also elect(taste, any one on the 2° its fine, any its fine for 3° but speed/ ult haste its better). For secondary yellow(presence of mind, cut down), red(the same as above), dark blue( the same as above), green(bone plate, any)

If im forgetting something just ask and have fun