The site Yumsugar ran seven great burger tips that one of its bloggers picked up from Bobby Flay at the Food & Wine Classic in Aspen, Colorado, a while ago. It's good advice here on the Fourth if you haven't yet started your fire. My favorite:

When forming the patty, make an indent with your thumb in the middle. This will ensure that the meat plumps nicely. Flatten the patty before placing on the grill. Never press down on the patty or flatten it while cooking. This will release the precious juices that are essential to a burger's flavor.

What's going on with the indentation suggestion is that the center of a burger usually swells when it cooks, leading to football-shaped patties. Indenting it ensures that even when it does puff up, even thickness is maintained.

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