Selecting Keywords

Search Engine Position Checker by Keyword
Check your site's position on search engines for specific keywords. This tool checks the first 50 results only. Check out other tools there.

Select smart keywords for your own SEO campaign
This free tool is provided by Google and is very helpful for selecting keywords. Type your keywords, and the tool will return synonyms and variations. This tool helps you get ideas for new keywords that can help you plan your SEO campaign.

Google Suggest
As you type, Google will offer suggestions and you will immediately see how many search results there are for each possibility. Very cool!

Wordtracker tool for targeted keyword selection
Wordtracker is famous in the SEO circles (although definitely not for this "keyword research guide" (pdf)  that you are offered to download free of charge after you've made a purchase). Wordtracker is considered the best keyword selection tool on the market, as it allows you to analyze and predict performance of your potential keywords. Wordtracker is indeed a simple sweet tool to use. The best value of this tool is that it actually shows you the number of times users typed particular keywords in the last 90 days. The tool is subscription based, so you can login to your account from anywhere you want.  They offer a free trial, but the trial version is not very helpful, since you can't practice with Google. If you are working on a small project, purchase a one-day subscription, it only costs a few dollars. We recommend using Wordtracker together with Google's Suggest and Google Keyword Tool as well as Google Sponsored Links that shows you what companies buy ads on Google Adwords for the keywords in question (all free).
 
All you need to know about AdWords directly from Google
It is best to learn about AdWords directly from Google. Note that it will take you approximately 5-6 hours to go through all lectures and associated quizzes. But these lectures will also help you if you decide to become a Qualified AdWords Professional, a lucrative designation offered by Google. We recommend joining the program, as it offers good financial incentives. Please note that you will need to satisfy a number of requirements, but none of them are challenging. You need to know how AdWords work and you need to make sure that you spent US $1,000.00 on AdWords in the last 90 days, either on your own account or for your clients. There is also an online multiple-choice exam that you need to pass by getting at least 75% answers correctly. If you've used Google Adwords yourself and reviewed a few lectures posted in the AdWords Learning Center, you will have no problem passing this exam.
 
Keyword Density Analyzer
Be patient and check all your static pages, one by one.