A set of truly excellent videos on building layouts can be found at Joe Fugate's Siskiyou Line. They are well worth the money.
All of these articles represent how I do things on my layout. I didn't invent any of this. I stand on the shoulder of the giants of model railroading. There are many ways to build a layout and they all work - this is not meant to imply that one way or better than any other - its just the way I currently do things.