That score is your author score. One of the things I did to raise mine, was to look up hubs on getting a high author score. Having raised my own score, I have since written one of my own, from my own experience, and my research.
Honestly the two best things for you to do to start out with is write quality hubs (well written, decent length, good pics, interesting) and become active on hubpages, such as asking questions like you just did, or answering them. Get involved in the forums, read others hubs, leave replies.
There are so much more than that, but those two things will get it to increase greatly.
By the way, it will change the most now. I know when i first joined, my score got as low as 8, and then two weeks later I was in the seventies. Just be patient, it will get there. At about a month, it was in the nineties, and it has stayed there since.