We all know that the Google Adwords keyword tool is only an estimator and is usually not very accurate at all in determining the search volume for keywords. So how do we find out which keywords have more value than others?
One good way of finding out is by running a Google Adwords campaign for those keywords prior to your SEO campaign and measuring the traffic/conversions that you get from that exercise.
What’s important to note in this case is that the kind of campaigns you should be running are for exact match keywords. These will give you more accurate keyword data as you will only be bidding on the exact keywords you are trying to research instead of any other additional variations. These are denoted in Adwords by the [ ] fields ,eg. [keyword].
Once these campaigns have been set up, you will then be able to look at the number of impressions that is being generated over a period of time. I recommend at least one week of bidding (on a high budget).
The data you get from this is typically very solid and you can be certain that the number of impressions you get from Adwords is accurate enough to make decisions on what keywords to then go and optimise for.