Short field landing... in a 172 I usually just fly on the almost point of the backside of the power curve - keep a little power in (as some would say dragging it in) on short final. Get low over the threshold, pull the power about a little bit (laterally) from where I want to be - always hits the spot.
The point being that there's enough drag created by a high AOA that when you pull the power you land a couple feet in front of you. It's seemed to work.
Soft field landing - just remember the points... 1) soft landing: Do what you have to do to make this happen...if you want to "cushion" the landing with power, you probably won't need too much power. 2) keep your nose up and enough power to not get stuck.
You should ask your CFI if you can go to a grass strip and experience everything.