I have never been able to work it out myself. I am sure you are going to get some really in depth answers here that hopefully do a good job of explaining it. I have pretty much just decided that I get what I get and I deal with it. It sucks sometimes, but it's more than I would have gotten had I made a post on Facebook or something like that. I used some of my liquid STEEM a little bit ago to lease some delegations so I could increase my SP temporarily and earn some more curation rewards. If you have enough SP curation can be pretty lucrative.