Survey the beach, and examine the position of the sun. For example, if the sun appears to be positioned to the left of the beach, then choose a spot that is further to the right, so that you can get a larger angle of umbrella coverage.
Open the umbrella, and hold in a position that provides maximum coverage. Experiment with different angles and locations until you find the most preferable one. Mark the spot in the sand with your foot.
Invest in an umbrella anchor that twists into the sand and holds your umbrella in place. You can find one at most beach supply shops or beach sections in stores. Use a small shovel if you do not have access to an anchor. Dig the spot with a small shovel about a foot in depth, and then insert the umbrella pole inside it. This anchors the umbrella and eliminates the problem of having to chase your umbrella in the wind or constantly adjust it for coverage.
Readjust the angle of your umbrella to compensate for the changing position of the sun. Tilt the top of the umbrella if your model has this feature, or push along the side of the pole to reposition it.