Your hubscore has nothing to do with your AdSense earnings except that you get a lot of exposures if your hub score is high. Exposure means traffic and you might get some AdSense clicks too. But your hubscore might affect your HP ads earnings as it depends upon traffic and impressions.
To increase your hubscore, you should:
1) Research carefully.
2) Reduce duplicate contents.
3) Write about evergreen topics like "How to say I love you!".
4) If you're writing about travel and places, include a Map capsule.
5) Tweet and Like your hub often. This will get more traffic and more exposure.
6) Don't publish the hub right away, wait for at least 5 days to publish the hub.
7) Carefully look at the spelling mistakes before you publish. If you keep on editing the hub once you've published, then the hubscore will take a lot of time to increase.
8) Create backlinks on SheToldMe, Redgage and Snipsly.
9) Promote your hubs on your Facebook profile and your HubPages profile.
10) Write more textual content.