Finding Keyword Rich Domains
By the time an SEO project comes your way the site you need to optimize probably already exists which means the domain name has already been chosen. However, sometimes you get in on a project early enough such that you can provide some input on a domain name. Generally, the choice of domain name starts with answering the question of whether you want a brand or descriptive domain. Both have their advantages.
I'll let the marketing folks out there describe to you why a brand is important and just assume that you're looking for the search engine optimization benefits that a descriptive domain name can bring you not only from a boost in rankings, but also a boost in click through rates from search result listings. With this in mind you want to select 2 or 3 keywords that describe your product or service while at the same time being a phrase that is commonly searched for. The shorter the better, of course. You also want to consider what pages on your site you're likely to have and how the topic of those pages will combine with your domain name.
For example, if you're setting up a site about SEO, your ideal domain is probably SEO.com. And knowing that you'll probably have pages about training, consulting, and copy writing you're able to confirm that your URLs will make sense i.e. seo.com/training/, seo.com/consulting/, and seo.com/consulting. Note that if you didn't take this extra step and instead registered seotraining.com you'd end up with more spam-like URLs such as seotraining.com/training/. The seotraining.com domain would of course be appropriate if your site focused on training alone.
This all sounds easy enough, right? Well the tough part will be finding a domain that isn't already registered. With my own projects I often have to wade through a 100 or so different domain names before I find one that is unregistered. With recent efforts I've had to resort to separating words with dashes because the non-dashed versions were unavailable.
For the actual research step I highly recommend this domain search tool: Bust A Name (a keyword poor domain, but a catchy one). With it you can enter individual keywords of interest and then let the tool do the combining and searching for you. Trust me, this will save you a lot of time!