It is the generally accepted protocol to choose a keyword that is growing to optimize one';s website. Is this not a self fulfilling prophecy? After all if more web designers use this keyword does it not follow that it will show more and more results ?
Re: keyword results
Your question seems to be more about organic rank than AdWords. You might try asking in the Webmaster Tools forum.
I'm really not sure what you are asking here. Designing a website around keywords to optimize for search is a bit outdated, I think. Keyword density is not really used much, and too many occurrences of your keyword on a page could actually get you penalized.
Create quality content that is unique and has value. That will do more for your organic ranking than building around keywords.
Best of Luck!