I had this problem recently and I figured it out. Here's how I did it.
I quickly figured out that I won't be able to achieve this by ending them individually. Because there will always be some left.
Instead, you have to make your environment unsuitable for their survival.
Only store food behind doors where the flies can't go. Keep your trash bags closed and take trash out frequently. Always wash your dishes immediately, so the flies can't feast on the leftovers. You should only have food out in the open if you're about to eat it; and do so without hesitation.
The fruitflies won't have anything to eat. After keeping this up for a few days, you will notice that they've all vanished.