One of the most important pieces in mapping out any SEO project is determining which keywords to target and how. There are a lot of great processes  for this, but one thing that’s highly valuable as you research keywords is an ability to go beyond the rough estimates keyword tools give you to get at a more precise estimation of how much traffic  you can expect from various keywords each month. This information allows you to:
- Prioritize one basket of keywords over another
- Make rough projections around how many leads and sales you can expect based on historical conversion data
- Determine, based on a keyword’s competitiveness  as well as how much traffic it will drive, if it’s worth your effort.
In this post we’ll walk through a couple of quick and easy ways to get at your keywords’ organic click-through rates .
Get Your Current SEO Click-Through Rates
Google Webmaster Tools  offers some fantastic data here within the search query report. You can grab rough impression, click, click-through rate, and ranking data on your search queries:
Obviously this gives us a view of our organic click-through rate, but we can also use this report to extrapolate out a rough estimate of how much additional traffic we would drive if we moved up in the rankings. For this we need to understand the rough distribution of click-through rate across organic search results.
Average Organic Click-Through Rates
In order to make a guess at how much additional traffic we’d drive if we moved up a spot or two in the rankings, or to guess at how much traffic a certain ranking on a term we’re considering targeting would yield, we need to understand the percentage of total traffic certain rankings typically drive.
Patrick Altoft had a nice synopsis  of a few different data points around click distribution, based on some leaked AOL data from 2006, the Webmaster Tools data and a recent Chitika study. The idea here isn’t necessarily to make predictions with any overly precise accuracy (that’s basically impossible) but rather to get some directionally useful information, so picking one of those data sets or averaging them together will work just fine.
From there, once you have a percentage estimate, you can use that to help you make an educated guess at what you’ll generate for a move up or down in the SERPs by:
- Looking at your current position and the rough expected CTR 
- Extrapolate from that number the total number of searches for that query
- Determine the percentage of that number your desired position should expect
Now you have a really good guess at the additional traffic you’ll drive from moving up. Similarly, if you have a global traffic estimate for a keyword you’re considering targeting, just calculate the expected traffic based on the percentage of traffic you’d get for a number one ranking (or whatever you think is attainable) and you’ll have a rough estimate of what that ranking would drive.
Again this is just a very rough estimate, but as you look at different terms to target and look for the best opportunities, understanding how much traffic you can expect from rankings on various terms can be extremely valuable.