If your paid search is languishing and you desire for some much needed optimization, a great place to get started is this article by Alex Cohen at Search Engine Watch. He outlines at least 43 points that you can drill in to in order to further optimize your paid search account.

I recommend starting from your landing page and working backwards through the search process. Your landing page is where the conversion/sale/goal will take place and presents your greatest asset with regards to optimization. Just improving conversion rate 5% will increase your bottom line dramatically. Once you make improvements on the page, work backwards looking at the ads, the structure of the ads, the campaigns, and ultimately the keywords.