These free analytics tools will allow you to track which keywords are sending you traffic, what keywords are profitable, and which keywords aren’t giving you a return on investment.  The tools allow you to focus on results, which can make your SEO efforts much more efficient.
They can also allow you to branch out to look for other areas of opportunity, to track conversions, and to see where your new optimization efforts should be focused

Keyword Research
These free tools can get you started on finding which keywords will provide the best opportunities and how much competition there is for each one.

Competitive Link Analysis Tools
With the weight given to incoming links in determining search engine rankings, you’ll want to have a window on what yours are doing for you and how you can get more of them. These tools will allow you to analyze your incoming link status compared to your competition. They can also help determine the best pages to link to your website.

Search Engine Rankings

This will allow you to check the status of your SEO and search engine marketing efforts by showing your progression through the ranks