This is the way I learned while working at a tailor shop. It is the strongest way to mend a hole. It doesn’t leave the look of “I bought these jeans with the holes in them.” Anyway, my example is on one of my husband’s favorite jeans. The hole is right next to another mend I did. The previous mend is how we met, read about it here. I wouldn’t recommend mending next to a mend, but I had to save the pants.
Good luck with all your mending!