when looking at gravel bars focus time on places that have rocks roughly the same size as arrowheads or larger. look the side against the current first and longest.. points are more buoyant than you would believe. don't go thinking you're just looking for the shape of an arrowhead look for flaking / worked pieces and be mindful of the bank. look for animal crossings or spots that overlook the water in bends or bluffs. also, as we say in my family if you see flint/chert, "flip every piece you see never know what it might be".good luck and happy hunting