Keyword research is an important SEO foundation tool for everyday writing, not just full scale research projects.
Keywords are a key element in every website and keyword research is at the foundation of SEO. Keywords don't just go into page titles, headings, and the copy of a page, but play a critical role in links, file names, and even the architecture of a site.
When we SEO practitioners think of keyword research, we often think of "full-blown" research projects, pulling and filtering through thousands of keyword phrases. This kind of research can't be understated, but sometimes it's more than we need. There are times when we just need to fine-tune a page, a blog post, or an online press release. You may already have your main target phrase figured out but are just looking for a couple supporting phrases, or trying to pick between phrases.
Keyword research doesn't have to be an all-or-nothing proposition, investing several hours of data collection and analysis. For this kind of quick, on-the-fly kind of research, there are some easy and free tools just a click away.
The most important thing to remember, with this or any kind of keyword research, is not to get too caught up in the numbers...it's not about the numbers, it's about the relative differences. Not all tools even provide numbers, but for those that do, any numbers they do provide represent only a small subset of searches. That one phrase received a certain number of searches isn't all that important; that it received 3 times as many searches as a synonym or the next closest phrase is important.
Two of the main keyword research providers, Keyword Discovery and Wordtracker, both offer limited but free tool access to their data.
Google provides access to their keyword data via their AdWords Keyword Tool, and you don't even need an AdWords account. Additionally, Google Trends just became even timelier with daily updating.
Or if you are looking for a one-click approach to the data from these and other tools, you might like Aaron Wall of SEO Book's Keyword Research Tool. One to watch for the future is the collection of tools that Microsoft is putting together, currently in demo, at adCenter Labs.
These are great tools for quick, day-to-day keyword research needs. All you need to do now is to make these tools part of your everyday writing routine.