Hi Mark,

My method has always been to look for a search term within the subject matter that I can optimize for. I have started a new site at: netmarketingcourse.net

I choose that domain name very closely and over time will target the phrase "internet marketing course" which gets a health amount of search traffic each day. I also choose a phrase that is very general in nature so I can promote anything "internet marketing". I usually always go for the exact search phrase, however this time I am testing out some google LSI stuff. This is why the domain starts with "net" rather than internet.

Google understands that "net" offer refers to "internet" ... again lsi stuff.

You can search Google with the following: ~net

Which returns related terms in bold, thus internet.

That being said I would stick with the exact phrase if you can find a domain name with the search term. I have a site that I built last year around "domain parking" that now ranks in the top 10 out of 5+ million results ;-)

This way after a while your driving quality target traffic to your "hub site".
Hope this helps.