Well the number one thing to do is to eliminate their habitat, essentially by reducing places that have standing water.
Cutting dead trees down or trimming some branches to let in more sunlight also helps as said sunlight also dries up the earth below it.
Now strictly talking about bug control, I personally have a mosquito magnet type of propane lure which burns propane and mimics human breath and sucks them in once they are too close.
Does it work? Yes. But in my personal case it is hard to place it in such a way as to lure all of them and away from you.
I have a couple of friends who have them and need to empty their bags on a weekly basis while in my case I seem to only need to empty it out once every 2 weeks to a month.
How much does it kill? I'd say a couple of thousand mosquitoes but I would keep mine even if it kills 500 since I rather have 500 less than on me.
As far as I know the mosquito magnet doesn't work on black flies, however there was another brand that has a. Big sticky paper panel where flies stick on while most mosquitoes got sucked in
I also have two uv lights that shock the mosquitoes as they fly into it.
I have looked into making some mosquito traps with tires (you can look up how to make them online) but never really got my hands around to making any (essentially creating standing water that you "filter" and keep the eggs from hatching and reducing their population. As far as I know it has to be filtered almost daily and for a big size lot it would take half a dozen over a couple of weeks to reduce their population.
Lastly, if you have a pond or a big standing puddle then you can buy pellets or "doughnuts" of a special kind of bacteria that eats the mosquito larvae. I have used these in the past with success on a drainage ditch that always stayed half full during summer.
P.s. even with said techniques you are looking at reducing their population and not eliminating them completely, but it will make bug spray more effective.
If you want to eliminate them then you can buy some insecticide and spray it on the house or fog it over the whole lot. As far as I remember permethrin is legal in canada and not that harmful to the environment. But after 1 to 2 rains the effect is almost gone. If you get a good dry season where nothing will wash it off then it can last a good month or two.
I know when I sprayed my lot for a party I had absolutely nothing flying or crawling in my yard for a week before it rained, then they started returning slowly.
Hope this helps, thankfully I don't have black flies in my neck of the woods.