I have never been able to pull ap tf off.
build order is usually:
boots/null-magic mantle/vamp scepter
then bf sword/merc treads
sheen -> triforce
then it is situational items like sotd/madreds/armor
Then infinity edge if need be
chalice of harmony-(so you can continuously hit with your wild cards early game, very awesome mr too)
boots( depened who your laning against)
then i go for lichbane for speed and even more mr
after lich bane you can either build towards survivability or more ap, i build more ap and backdoor, but the only way to know what you like is to try it out mate.