I've always struggled on this one, but my most recent instuctor got me as close to acceptable as I'm gonna be:
As you turn final put on full flap, forget the approach speed just chuck the nose down and lose a lot of height (staying in the white arc of course).
Adopt a very nose high attitude (don't know approach speed in C150's I'm afraid). Drag is very high 'cos of the attitude so you MUST do a power-on landing (my instructor reckoned that was the secret ingredient).
I was taught in a PA28 and I never had problems of floating - quite the opposite (and what's wrong with dropping fromn 15ft?)!
BUT,
1 I hate doing them 'cos engine failure means curtains - there's no way you can make the field
2 My PPL GFT examiner hated them too for the same reasons. In his words: "I'd rather hit a tree at 30kts, than drop short at 65kts". He asked me to prove I could do a 'drop late from high' short field in the same test.