I know most of you are talking about food on the smoker, but for me, the biggest PITA is getting a good burger off of a charcoal grill. It never fails that the burger will either fall apart on the grill or end up dry as a bone.
What's your burger mix?
I like to use 80% ground (the higher fat content stuff), and 20% ground venison. I have a ton of it, but if you don't, try using either ground turkey, lamb, or even a leaner grind of beef.
I like to use a binder, so I'll add a panko or italian bread crumbs, one egg, all the spices and plenty of mustard. Finely chopped, grilled onions are an option.
Mix thoroughly by hand, and hand form the patties (I don't do a lot of measuring, so I'm guessing my handful of meat is roughly 6-8 oz?).
I put these on a cookie sheet, I like to add a dollop of teriyaki glaze to the top, cover and let come to room temp.
Get a greased grill good and hot, maybe 500 degrees, and let them sear on each side till the meat doesn't stick. Turn so you get nice grill hatchmarks, and then let them rest tented on a platter. ETA: Forgot to add that I turn down the heat after the first turn, maybe 350ish? In all honesty the thermometer on my grill died a couple years ago and I tend to do it by feel...
Moist, don't stick, and my kids won't eat a fast food burger anymore, they're so good.
I guess the key is letting them sear, and remembering that they'll continue to cook when they're pulled off. I hope that helps, and if it doesn't, you can always blame me...