With all keyword research, you'll need to apply a Human touch. Keyword research is not an entire objective undertaken purely based on statistics. You will need to follow your instincts as you build and hone your keyword list and strategy.
It's important to think about how users search for the products and services that they seek online. There has been a wealth of research undertaken on the subject, and our own patterns and techniques as search users can teach us much about how others use search.
Most of the research on user search patterns leads to a few basic conclusions. First, new users seeking information online tend to enter either longer search strings or shorter search strings than experienced users. A new user might enter a query such as The hospital nearest to Oldham Road in Oklahoma City. If you ever have the opportunity to observe an inexperienced user make use of a search engine for the first time...