It seems something in your experience is telling you to first pick a keyword, then write a website around that. Why would you do this? You have to pick a niche you have experience with, or something you are passionate about. That is the only way to have your content come out good and be of value to a visitor. Let's say that you picked the cheap flights keyword as recommended above. What on earth would you write about if you know nothing about cheap flights? Focus on creating quality content in something you are passionate about, drive the traffic, the clicks will follow trust me. That's not to say that you shouldn't research your keywords though. You might be passionate about topic ABC, but if ABC only gets 1000 visitors a month, it may not be worth it.