Super odd! I saw on Pinterest, cut limes in half, stud with whole cloves and set them around wherever flies are. Not only do they work, they are pretty. And a bonus, Pierre- when the sun warms them, it smells delicious! I do not know why it works, but it really does.
These are all of our easy, natural, and proven ways to keep mosquitoes out of your yard: https://chemistrycachet.com/natural-ways-to-keep-mosquitoes-away-this-summer/
Lots of helpful tips here: https://www.craftylittlegnome.com/diy-mosquito-repellent/
Get rid of any standing water. If you have water features, add mosquito pellets to kill them. Personally, I love my thermocell. It's a small device that works with butane and chemical pads to confuse the mosquitos. We use it any time we're outside at dusk. If you're going to be sitting on the patio in the evening, a box fan works well too.