once you get a feeling for pumping, it will never fade and only get better over time. basically, once you become moderately comfortable with skating around on something like a mini ramp, you'll naturally try to learn stuff.
however, speed is key. like mullet man said earliar, charging shit is the only way to go. when you're fooling around or trying to learn easy stuff, it should be a inclination to learn how to go faster and with alot of tricks (if not most) come out of the trick with more speed than you had going into it.
you'll figure out that transistion skating has so much to do with how you control and manipulate your momentum, and you'll get hyped. I think with me and alot of other dudes, once you really start skating tranny, you'll do alot of your 'street skating' tricks with so much more speed.
*I guess learning on smaller (or smallest) thing you can find is helpful, but when did going big ever hurt anyone? honestly, dudes who skate legit vert probably have and always will learn how to skate on large ramps. if you skate bigger ramps, smaller transistion becomes a much easier and fun task. think about it this way: a dude who skates a 5 foot mini has alot more of a trick selection on something small than a dude who only skates small transistion does on a 5 foot mini ramp.