Bees as in honey bees and bumble bees? Or jellow jackets and wasps? Look up all four on google images if you aren't sure what comes around. I suggest this because people tend to use the words interchangeably. If it is the latter two you should put out traps in the spring when it starts to warm up to catch queens who are looking for a place to establish a hive. You eliminate the queen early it prevents hives. You can also fll cracks in the parts of your house if they infiltrate into eaves or siding gaps. Fill any holes in the ground from moles and chipmunks as they will make nests there. If a hive appears high up on your home get a spray nozzle with a spot for soap (like for cleaning cars) that attaches to a hose and fill the reservoir with dish soap and spray everything down at night when they are all inside as soapy water absolutely destroys them. For ground hives, go out at night, place a light near but not over the hole as guard wasps may come out, pour liquid dish soap down the hole and then put a hose down as well, the soapy water will kill everything--may take a few nights to get them all.

As for bees, you can't really stop a swarm. If anyone has bee hives near you they should be managing their hive populations well enough to prevent swarms but even then bees may split off and try to find new places. If a BEE swarm is nearby look for bee groups online as they will happily come get free bee for themselves. We need bees and when in a swarm they have no hive to protect and are pretty harmless. They will usually fly off eventually.