start focusing on getting quality content that is optimized for your keywords. Also focus on backlink building.
Backlinking is free and also important, just make some effort each to trade link with your partners with similar theme. There are free tools out there can help you manage it easily.
First try to make good quality and quantity backlinks with doing social bookmarking, blog commenting, forum posting, article submission, etc. For doing effective seo use high PR as well as do follow directories.
Let me add to the conversation. Yes - part of the answers are optimized pages and backlinking (though, I think there is to much emphasis on backlinking - unless it's done for promotional causes), but there is another thing. Try to make your website as big as possible. Put articles on the site and once these pages become indexed - throw them on article directories and web 2.0 props so that you can get some referral traffic as well.