Here's how I do it:
1. Enter your keyword, smack GENERATE KEYWORDS
2. Select Match type: EXACT (the others just give you a false sense of opportunity)
3. In the organic column: SEO TRAFFIC (SEOT) enter is 25 (this will filter out anything below approx. 100 searches - it's practically the same as entering 100 into the "Total Searches" above it. By entering it into the SEOT box, it's already open so one less click)
4. Hit REFRESH FILTERS (Now we've gotten rid of the "weeds")
5. Hit ANALYZE KEYWORDS
6. Sort by SEOTCR COLUMN.
As the instructions say: "This is the ratio of SEOTC to SEOC. A low score can indicate weak competition in a market." Guess what? You'll notice that everything in the single digits will have less than 50,000 pages in the SEOTC column next to it.
I first glance in the SEOTCR column: Starting at the top, how many single digits (below 10%) are there? Focus on these.
Second glance: How many SEARCHES are there for each of the low SEOTCR's? Don't forget, these are exact searches PER DAY. If you can get to the top of the SERPS you might get 25% of that. If you're off of the front page of Google, you're wasting your time. You'll require at least 100 searches per day. You'll shoot for 200. HOPE you can get 300-500. Just for laughs, you can look at a 1,000.
7. Pick a keyword and click the magnifying glass/key icon, click the tab and generate results.
Is it green all the way up the PR and BLP column? Then you got a winner. It hardly ever is..so you've got to develop the art of looking at this data. (see above for details)
I then have networksolutions.com open in a browser and see if the domain is available for the keyword you're looking at. Are the .com's, .net's and org's already taken? Then this stream has probably already been mined for gold nugggets. Move on. Usually the .org domain is available. If so do this:
CLICK - ADD CUSTOM URLS button and add the .com and .net URL of the keyword you're looking for. (Hit Generate results.) Since these domains already exist and ARE the keyword you're looking for, you can get a good idea how far you'll rank when you first start. You'll find plenty of parked domains that aren't doing anything. They're not your competition. But if the .com version of your keyword looks like somebody has tried to promote it and it's not showing up in the SERPs, then you'll have to figure out why. It's probably because the competition is tough in this neighborhood.
When done: REPEAT A FUCKING HUNDRED TIMES.

It's very tough to find good keywords. I would EASILY say the ratio is 100:1 before I buy a keyword. Anyone else have an estimate?