I am not sure how others do it, but to me there are many solutions to site design. I create a series of sketches from simple to crazy that allows the client to consider multiple possibilities. Usually, the client will take bits and pieces from all the sketches. These are then put together into a final sketch. This in turn goes into working drawings that can go out to contractors for bids. The sketches and drawings are only a guide. The most important part of the process is field observation. This is where the puzzle comes together.