I would like to add to the suggestion list:
1) Create linkbait. This sounds bad, but isn't. It's simply quality content that people like to link to (typically informative). For more on linkbaiting,
click here.
2) Unless you plan on selling advertising or selling the site later, don't worry too much about PageRank. As was said above, it doesn't help you with SERPs nor is it indicative of traffic.
3) Obey the Google rules. You definitely don't want to get a -30, -950, or de-indexation penalty for not obeying the rules.
Google Webmaster Guidelines
4) Content content content
5) Have constantly-updated content that will draw return visitors. Forums, blogs, etc. tend to do well in this area. Consider offering a newsletter that your viewers can sign up for. This is a good way to remind your viewers that you're still there, and introduce new services, etc. Don't spam though.