I live in an area that's loaded with mosquitos, some the size of small birds. We have lot's of wetlands around where they breed and are surrounded by woods. I have the big cordless mosquito magnet and it works on our yard which is an acre, but doesn't get them all. I also have to fill the propane tank every 3 weeks. We call the Bristol County Mosquito Control and they spray our street every couple of weeks, too. It seems to help a bit.
I've tried everything and the thing that works best (that can be bought at a store) is the Cutter Backyard Bug Spray. You hook it up to your hose and spray the grass, bushes, trees, etc... I do it in the morning and it dries in no time and we get no mosquitos for about 2 weeks. It's cheap, too.
Backyard? Bug Control Concentrate
And definitely put up some bat houses if you can. The bats eat a ton of mosquitos and are pretty cool to watch at night.