We sell fly bags that that work quite well, but at the end of the day flies go where they want to go and if you have pet waste and trash cans that have a “more attractive” smell to the flies than what you are putting out to kill them, then there is not much you can do about that.
Our fly spot bait is very popular: http://www.domyownpestcontrol.com/maxforce-fly-spot-bait-p-393.html
Outdoor fly traps
Catchmaster disposable fly bag: http://www.domyownpestcontrol.com/catchmaster-disposable-fly-trap-9758-p-1837.html
Indoor fly trap
Fly Web Fly Light: http://www.domyownpestcontrol.com/flyweb-fly-light-p-436.html
These should help diminish the numbers greatly. However, as far as a 100% fly control solution for outside no matter what you have around attracting them…..we have yet to ever find that product.