If making your own patties, use a scale to weigh the portions. This will ensure you burgers cook evenly — avoid the temptation for a massive burger! Six ounces is normally good, unless you are making a slider, then 1.5oz-2oz is better.
Now while handling your meat, don’t overwork. Using wet hands to form burger patties will keep them from sticking. Then gently press the patties, sprinkle them with sea salt, and make a dimple in the center of each burger. As the burger cooks the dimple will even out, no more dimple.