Follow the leader
Websites are a great business tool anyway you look at them. I’ve recently been re-optimizing Griffio’s meta tags and it’s fairly easy with the help of your leading competitors. Whatever it is you sell, Google it, and then see who comes on top. Take the top 5 natural rankings and view their meta data (to do so, click on View, then Source on your browser. The meta tag content should be near the top). See what keywords your competitors are using and apply as needed to your own. This WON’T make your natural ranking leap right up to the top, but it’s a foot in the right direction.