Sprays work well but stink the place out and coat everything in a sticky toxin.
And those glowing blue lights don't seem to attract our flies at all - particularly during the day when the room is filled with daylight.
A big fly-catcher plant works quite well (if and when the flies happen to go near it) but it doesn't flourish in a south-facing kitchen.
The best method I have come up with to date is to switch on the vacuum cleaner (snake variety), aim the long barrel slowly at the fly, like a snooker cue, and BANG . . . he's sucked up and gone. Five or six careful snooker shots like that and the five or six flies are removed from the kitchen within the five minutes it takes to aim carefully. Very effective, instant gratification, wonderful feelings of revenge, but there's this bloody great vacuum with its long snake attachment and wire sitting in the corner of kitchen all the time.
Any better method?