Since you've been here two weeks, your present score isn't bad. It can take newer Hubbers a little while (a very little while) to see scores get to where they may eventually kind of settle.
As far as your score goes (and your score is different from whether your Hubs earn or not), chances are writing one a week (if it's a fairly good one) will "do". If I write a couple of Hubs within a short time I notice a temporary drop in my score. (I think, until things "settled".)
More Hubs are better as far as increasing your chances of earning goes (in general, and unless you hit a couple of particularly successful subjects).
You didn't ask about earnings, though; so back to the score: For now, with the score you have, if you keep writing at whatever rate you want (and write decent-quality Hubs) chances are you're score will go up. Your score right now isn't bad at all. Generally, just don't worry about the score and write what you think is a quality Hub.