Look for Water Ripples
If you are hunting creatures that use the water, for example moose, or puddle ducks... look for ripples. Yes, ripples! If you actually see the animal, it can also see you, and it may be too late. But if you come around a bend, and look for and see the ripples - generated by what is ahead and still out of sight, you have "spotted" your animal before it can spot you.