As always start with the right equipment. in this case, know what you're getting into with different varieties of ground beef. Avoid the stuff that comes in packages generically labeled "ground beef." This is usually a mixture of several cuts of meat and can have as much as 30-percent fat. Yes, fat is flavor, but at that high a percentage, your burgers will be greasy. Instead, look for ground chuck (about 20-percent fat), ground sirloin (about 15-percent fat), ground round if you're dieting (about 10-percent fat), or any mixture of the three. If you're feeling adventurous, throw ground lamb, turkey or pork into the mix. But remember, unlike beef, turkey and pork need to be cooked all the way through, no pink in the center.
Season your meat according to your taste, with one exception: DO NOT add salt more than a few minutes in advance of cooking; it will dry out and toughen the meat. Instead, season the meat with pepper, salt-free Cajun or Creole seasoning, cayenne pepper — whatever you like. Then, mix with your hands. Be gentle and quick; over-mixing will toughen the meat.
Before forming the patties, run your hands under cold water and leave them slightly damp. Keeping your hands and the meat cold while working prevents the fat from melting and the beef from toughening.
The thickness of the patties should be determined by the temperature to which you plan to cook them. If you prefer a pink center, your patties should be at least an inch think to allow the outside to form a proper crust without overcooking the center. If your taste is for medium-well to well-done burgers (or if you are using pork or turkey), aim for patties no thicker than 3/4-inch so you don't have to burn the outside to cook all the pink out of the center. Press a small indentation into the center of the patty to help it cook thoroughly in the middle without overcooking the outside. As the burger cooks, it will plump, and no one will be able to see the dent!
While you prepare the grill, keep the patties refrigerated. The cooler the patties are when they hit the grill, the better they will hold together. Before you light your fire, grease the grill, either by spraying it with nonstick cooking spray or rubbing lightly with olive oil. This will also keep the burgers together better, because the more you have to force the spatula under the meat, the more likely you are to break the patties apart. While the grill is heating, sprinkle salt as desired on the outside of the patties. At this stage, it will help bring out the flavor of the meat without drawing out the juices.
While cooking, do not press the burgers with a spatula. That squeezes out the juices, losing the flavor to the flames. Sear both sides of each patty over high heat, then move off the high flames to cook through. There are two ways to tell when a burger is done — the density and the juices. To judge by density, gently poke the center (again, so not press it down). Medium-rare will be firm on the outside, but overall still squishy. Medium is almost firm to the touch. Well-done id firm throughout. Also check the juices. When they begin to surface on the top of the patty, it's medium; when they run clear, it's medium-well. Serve 'em hot and topped with the desired fixings!