Optimising the pages and developing backlinks is what you need to spend time on.
Depending on the site, the best place to start developing backlinks is get submitting to directories (or get a monkey to do it for you).
You want to find the directories that don't use sneaky redirects though as that funks up any chance of passing PR. Basically take a look at the entries in the directories and go to a couple of the listed sites - check that the directory is quoted as a backlink in Google by doing a backlink check on the site.
Loads of directories here -
http://www.isedb.com/html/Web_Directories/
In WebCEO there's a nice feature to check how optimised your pages are.
That's fuckin' ingenious, if I understand it correctly. It's a Swiss fuckin' watch.