You are now opening your mind the fruits below our feet as we pass everyday come fall. Some years the trees seem to never stop dropping 'corns. In other years, even the biggest oak produces nothing. In years of abundance, we call them Mast years and much celebrating is done between us and the wildlife. It is important to be mindful of where you harvest. Do so in areas where you have permission by the landowner. Try to stick in areas that have low grass underneath, this helps you stay clean of ticks and other insects. Go for green or brown, blemish/damage free nut. Try to avoid collecting right after a rain storm, let the air and sun dry them a bit before harvesting.
Collect any way that seems best to you. Rake and barrel, nut weasel, bag-a-nut, hand pick, vacuum, etc... whatever way you do it, sort the good from the bad. A good method that is somewhat reliable is by dumping them all in water, the ones that sink are typically the good ones. This helps clean the shell and filter out most of the bad. If the acorns of really dry or its been a few days since collecting, expect even good ones to float.