AdWords Keywords

I think most of us use the Word Tracker Keyword tool at http://freekeywords.wordtracker.com/

While the Google tool is excellent too, Wordtracker gives you actual numbers for daily searches and you can tell a bit better which ones are searched more. Tip - type in a partial term instead of an exact one to start. You might find extra phrases outside of what you think are the best ones. For instance, if you are looking at "Mustang headlights", people may call them headlights, head lights, head lamps, etc. Type in "Mustang" first and you will usually find all the top terms in the order of importance.

Another example, "Las Vegas Homes". Do they search for "homes", "houses", "home", "house", or perhaps "condos" is better. Type in "Las Vegas" first and see how many terms are available to choose from and which are the highest in value.

Use the different Keyword suggestion tools, here's one –
https://adwords.google.com/select/KeywordToolExternal