1: Original and Fresh Content
Present your visitors content they cannot find anywhere else. Not all your content has to be 100% original, but a good percentage of your site should have original content. People are more likely to read information they havent read before. Add new content to your site regularly.

2: Surveys
Hold a survey/poll on your site. Or have visitors email their vote or opinion. People love to give their opinion. They'll also come back to check the status of the survey and again to view the results.

3: Prize Draws
Hold a monthly prize draw on your site. The prizes should be something of interest or value to your visitors and of course related to your site. Most people who enter will continually come back to your site to check the results. Keep it monthly don'y be lazy and make it tri-monthly or six monthly. You can also list your site on a prize draw directory and draw even more traffic.

4: Quizes
Run a quiz or a series of trivia questions. Post the correct answers weekly on your site. The people who take part will want to come back to your site to see if they were right.

5: News
Supply news stories related to your site topic. People want current and up-to-date news. If you can be their first source, they'll become repeat visitors to your site.

6: Jokes
Give your visitors a little humor. Don't be so serious; tell them a joke now and then. If they associate your web site with being happy they will keep coming back. It will also make you seem more approachable and human.

7: Free Stuff
Everyone loves to get free stuff. List free stuff on your site. It could be anything, software, services, sample products, e-books etc. The freebies should be related to your site topic. Keep the freebies coming and your visitors will return regulary.

8. Directories
Tell your subscribers about sites related to your site topic. The sites should be helpful and/or interesting. Become your readers site directory and they will come back.

9: Forums
Set up a forum on your site. When visitors post they can request they are emailed if somebody else posts to their post. They'll come back to the site when they get this email. Maybe post again or check other posts and post there. Essentially they then also build you fresh new content.

10: RSS Feeds
Convert new content you add to your site into an RSS feed. Visitors can sign up to your feed and your content will be permanently displayed in their RSS aggregator. As long as you regularly update the feed visitors will come back to your site.