As DAR says, know how to operate what you have. Read the POH. I'm always amazed how many pilot's have never read the POH of the aircraft they fly; just going on received wisdom. I like reading POH's being of a technical bent but there's no reason for anyone not to have an hour looking through it.
As for the difference there's not much TBH. Half an hour in the cct should be sufficient. You will notice that you need rudder on the take off roll to keep straight and also in the climb. Funnily enough I learned in a 172 and then converted to a 152 later. I was that used to putting a bit of pressure on my right foot on the take off roll that I started to drift off the runway in the 152. Soon corrected and not forgotten.
Edit: By the way the 40 degree 'barn door' flap setting on the older 172's is fantastic, that extra ten degrees is like running into a marshmallow when you select it. One of the one's I fly is 'K' version, a '68 and it is superb at steep approaches into short fields with obstacles.
Last edited by thing; 16th Jun 2016 at 19:07.