You should do SEO to get more traffic from search engines but you also need to keep your site interesting for visitors so people will come back. Other ways are using social website to promote your site, using forums, creating promotional videos, and others. There a lot of information on the web for generating traffic. You can even do offline promotional like advertising using flyers.
The are plenty of ways to get traffic to your site. Banner advertising, forum advertising, Adwords, article writing, forum promotion, getting affiliates to promote your site etc. Some methods are more effective than others depending on the type of site you own.
NOTHING new under the sun. Don't fall for any scams. Basic SEO and Content creation should cover you if you keep it real and add value. But you don't absolutely need a site or domain name in order to make serious money...