Give it time, I think it took me like half a year from the moment I started playing to get a perfect unit from Star Rushes Either way, to level up the skill you can do Tuesday and Friday dailies and hope that you'll get Rainbow Spirits. They have a chance to level up the skill. As for unit points, it's not that important I guess, but if you are after a collection of perfect units like me, you can hope that some day Nutaku will implement most of the content that DMM - the place where this game is coming from, have in their version.