Another thing would be to try and get a couple synergies between your mons with their traits. If you double up on some of their traits, when they level up they are more likely to get stuff that supports said trait and you can get some cool combinations/auras!
~Silver_Ermine~
http://24.media.tumblr.com/tumblr_m9r5hhXQbJ1rbct63o1_500.gif