You have to try number of things..
1. Topic itself should be of general interest. Write the topic in engaging manner. The hub should be helpful and / or entertaining.
2. Post links of the hub on the forums
3. Post links of the hub on some of your other hubs.
4. Put the link on your facebook or twitter profile.
Enjoy new visitors as google and other search engine catch on. If you have a good topic that people search on, then your hub becomes a classic. Enjoy some of my hubs.. which has been visited by over 1 million surfers.