How do I keep the flies away at 4th party here at the house?

Ok guys, all the fam is coming for 4th of July bash at my house and I want to do a big spread of foods out back by the pool. Anyone have any solutions, that work, to keep the flies away?? I have tried the lemons with clove spice and it didnt work that great I have tried that fly paper thing that hangs and it sucks. So? Please help!!! Have a safe 4th!