Obviously the criteria for people just starting out with SEO will be lower than for some of us that has more experience and I think it'll be interesting to see how different marketer's evaluate the keywords they want to target.
We'll start with me.
Right now I am targeting keywords with at least 30 searches a day and with fewer than
35 000 competing websites for that keyword or keyword phrase. I use this free tool to do my research Keyword research service for search engine placement, Google keyword tracking tools, web site promotion software
Then once i found a phrase that matches the above criteria I will do a google search for that phrase and see what comes up. Sometimes there are quite a few competitors but I can see right away that they don't know what they are doing and I know I can get a spot on the first page.Other times I see there are some fierce competition and I'll leave it to spend my time with the less competitive ones.
This technique has been working well for me and I am finding the first page of google for most of the keywords I am targeting which makes me want to start targeting more competitive keywords and see what happens.