Beef makes the best hamburgers.
While mixing the meat add a little Worcestershire sauce, onion and or garlic powder, and if the meat is too loose an egg to bind it up. Make sure the meat is well mixed but don’t over beat it.
This is also important to remember when you are forming your patties. You want consistent patties but you don’t want to squeeze them too tight and ruin the texture of the meat.
A pro tip is to indent your patties in the middle with your thumb. This will stop them from becoming UFO shaped on the grill.