In a light plane, you definitely want to avoid water unless you are on a plane with floats. If the wheels are down the when you touchdown in the water there is a high probability of wheels digging in and the plane flipping over nose first. This type of accident is often not survivable, broken necks, etc. When I learned to fly amphibians one of the first things you were taught was to verbally repeat "land on land, gear down; land on water, gear up" before every landing.
Landing on smooth damp sand can be like landing on pavement. You land normally and just ensure you keep you momentum up until you get to your parking spot. This type of beach landing is pretty common in Mexico. The hardest part is usually the taxing because you leave the damp sand and end up going into soft dry sand which requires power which throws up sand that abrades the paint on your plane.