There has been a quite a bit written on this subject, but I give three main guidelines.
1. Write on very niche topics and pick three word keyphrases to target for search traffic.
2. Title your hub with the phrase of your most desired keywords.
3. Write 30+ hubs on one topic and interlink the pages together.
Do this well and you'll find success. Find more details in this Hub http://hubpages.com/hub/Getting-HubPages-to-Work-f...