LPT: If you have a fly in your house and it is still light outside, make your house as dark as possible. Then open up a door or window that is closest to the fly and letting the most light in. The fly will fly through the door or window almost immediately.

When it gets warm outside there are usually flies outside my place (mainly because of my neighbor) and usually one fly will manage to get in to my place. This would drive me nuts and I would try to hunt down the fly only to fail and have it remain in the house for multiple days. Then I figured this technique out and have had a 100% success rate and best part is that other flies won't enter your place because of how dark it is compared to outside.