Look for a narrow gap in breaking waves
Watch for darker, calmer water between breaking waves
Notice water moving steadily seaward
Spot foam, seaweed, or debris moving away from shore
Check for a line of choppy, disturbed water
Look for a channel cutting through the surf
Notice waves breaking on either side but not in one spot
Watch for unusual color differences in the water
Look for sand being pulled offshore
Observe if swimmers or objects seem to drift out quickly