Choose your weapon for fly control
The first—and most obvious—option is an insect spray. This works quickly and kills on contact, so it can provide immediate relief, to an extent. For a more long-term solution, you may want to consider a fly trap or fly light. These provide ongoing protection, and can quickly cut down on your fly invasion—and possibly even get rid of it completely.
Using a combination of products—say, by using a packaged insect control kit—will provide you with the ultimate protection against these annoying pests.