When I am preparing for a tournament I spend most of my time "mapping" the greens and a surrounding area of about 30 yards to include bunkers, swails, or anything else not seen from the fairway. There are several ways to do this but my procedure is as follows:
1. Either buy a yardage book of the course if it has a quality drawing of the green or go to google earth and print out pictures of the course and each green. You would be surprised what kind of detail you can get from this. Google earth will also give you an exact "true north" position for each hole. This is important for "grain" and wind direction. If neither of these is available I draw it as acurately as possible.
2. Once I have a green diagram, I pace the green depth front to back, side to side, and also diagonally if I feel I may be coming in from an odd angle such as par 5's or short par 4's.
3. As I am pacing these areas I also note distances to ridges, bunker edges, downslopes, etc, and place directional arrows on areas where there is significant slopes or run-off areas.
4. Once I have the green and surrounds complete I look for potential hole locations and mark those. Once I have these I create "go spots" and "no-go spots". When playing a tournament I often do not have the luxury of guessing. I need to know that I have a "green light" to a flag or not. I also make note of green "breaks", firmness, and pace.
I try to play at least two practice rounds in order to become familiar with the course. I do not spend as much time mapping the course because most things are in front of you and I use a rangefinder. If I am not able to use a rangefinder then I spend more time mapping the course as well.
Hope this helps. I would love to hear from some of the pro caddies out there to see what they do for their players.
And here's another excerpt from that very thread.
I use true north as a reference only. When the wind is coming from the West/Northwest I can mark it on each hole so the "swirls" do not confuse me. Also if you are playing in an area where everything breaks toward the ocean, or Indio, or whatever, I can always have that reference.
For those who play on bermuda, grain is always an issue. The grain will typically grow toward the west (setting sun). Once again having a reference helps to eliminate doubt and is by no means an absolute.
Here's a video of Jeff at the old AT&T tournament that used to be held at TPC Sugarloaf just outside of Atlanta.