I would suggest targeting long tail keywords within you niche, "low hanging fruit" so to speak.
You should also try using www.xml-sitemaps.com
to create your site maps.
Have your HTML validated through W3C tool so that you'll get an idea of any syntax errors. You can check how your site stacks up to others with nichewatch.com
. From there you can figure out what keywords are less competitors and try targeting those first. You'll also know what your competitors are doing that's making them rank really high.
Don't forget to leverage sites like HubPages.com and (to a lesser extent) WetPaint to get some incoming links.