Theres a good
seo guide here, Not everthing mind, Keywords doesn't mean so much anymore, their are so many variables.
Keywords should be based on demograpghics/psychographics.
I.E who your targeting, what will they search for? Also the uniqueness of key words.
Web Host, as a keyword will probably return around 50 million results, so it's VERY competetive and VERY hard to become number one in those results, Where as something like Server Host would return under the 10 million mark, so which one would give you the better odds of being number one in? But then who is going to search 'Server Host'... is it worth being number one?
And so on and so on.
Also... supposadly, number 2 in google is better than number 1, because people are used to the sponsored results that people generally out of habbit skip the first one :o
Don't know how accurate that is though [: