Use Hub Hopper to read others' hubs and rank/comment on those hubs you enjoy or find interesting.
Follow some hubbers and leave fan mail telling them why you like their hubs.
Respond to comments on your hubs.
Keep publishing hubs.
Utilize the editor... add images and other contributory items to your hubs.
Increase your Hub Karma. You can find out more about this through the search box at the top of each page.