There are many different keyword research tools out there to choose from. For example, market samurai,
imeye traffic travis, the actual google keyword tool, as well as many others. The trick is knowing what each does and seeing if it’s applicable to your needs. You might be looking for just some high traffic phrases to boost your traffic to your site. Or, you are looking for new related keywords to add visitors to your blog. Either way, you want to use a tool that will get you related words and their searches in the search engines. The only way to know for sure which tool is best for you is to test them. Try to look for trials of each and pick the best one.