Keep content on your own site. The classic example are blogs, certain large directories give advertisers the ability to "blog" which does a lot for them and little for you. If you like blogging, have one on your own site, and use it to create meaningful and engaging content which will bring traffic to your site not someone else.
Make sure your sites links all work, "Google" your site, make sure all links point to pages that still exist on your site, especially if you have had a site update recently where page names may have changed.
Create some links in content to other pages on your site, in the introduction perhaps link to your profile, or news page. Your front page gets more traffic than any so links off it are more valuable than perhaps other links.
Check your image sizes, do not upload massive images into your CMS system even if it allows it. Google factors page load speed into its ranking equations, and nothing slows a page down like images, especially large ones.
Cheat, well not really but there is nothing wrong with looking at how your competitors do things, what are their key words and phrases, where do they advertise for example. A bit of research round forums and other sites may produce some useful ideas you can apply to your own site