I would try and polarize your range if you want to 3bet light. That is, 3bet all of your big value hands, AA, KK, AK, QQ and then a bunch of other speculative type hands that can flop big once in awhile but are too weak to call a raise with. This might be some hands like A4s, 89s, KTs.
Try to avoid 3betting really good hands like JJ, TT, 99, KQs that have huge value but can't stand a 4bet and can get you into all sorts of tricky situations postflop in a bloated pot. By polarizing your range you keep your decisions simple which is most definitely a good thing especially for beginners.
But all in all, I really don't recommend 3betting light very often at the micros (assuming that is where you play). You should be 3betting for value the large majority of the time.