Putts break away from hills
Don't forget the obvious. Putts will break away from greenside bumps, hills and rises, especially if they're close to the line of your putt.
Putts break away from the clubhouse
While not always true, clubhouses are normally built on the highest point on the course, usually for drainage purposes. Look for home, and you'll get a good idea of the general lay of the land -- information that can come in handy when you can't tell exactly which way a putt falls.
Putts break toward the sun
The grass on the green grows all day long, following the path of the sun. In the late afternoon, when the blades are at their longest, greens feature a serious grain toward the setting sun. Your putts will break with the grain. This clue is especially important when playing on long-blade Bermuda grass.
Putts break toward water
For obvious drainage reasons, greens will slope toward the nearest body of water. On oceanside courses, don't underestimate the natural roll of terrain toward the sea -- putts break especially hard toward the agua here.
Putts break away from bunkers
The last thing a course designer -- and especially the superintendent -- wants is water draining into a bunker. More often than not, the green slopes away from the sand to avoid extra bunker maintenance.
Putts break toward collection areas
Those funny, tightly mown greenside spots that your ball finds when you short-side the green are always below the level of the putting surface, and they usually house a drain at the lowest point. If you're putting near one of these collection areas, the break will favor that direction.