Many things are being discovered anew these days by people who are now working online in a serious way for the first time. User experience (UX) design is one of this. This clear article lays our the process in six steps (in practice you'll find that you're doing these things concurrently). Some of the examples aren't great (particularly the SouthWest Airlines example) and the use of the term 'brand' instead of 'purpose' or 'goal' is objectionable, but the core concept - understand your purpose, understand your users - is sound. And though this article isn't everything it could be, it's clear enough, detailed enough and accurate enough to be a good starting point.