You guys have hit on the Big 3: patience, temps and smoke. But here's four more:
1.) Putting a piece of raw meat over a smoky, low-heat fire ain't rocket science, so don't make it so.
2.) A bunch of high-dollar equipment is not required. I know and learned from a lot of rednecks who cook great cue with only a homemade smoker, a knife, a fork and aluminum foil. On the other hand, I know gadget gurus who can't turn out a decent pork butt to save their soul.
3.) Rubs are fun, but optional. Same with mops. A hunk of meat with salt and fresh-ground black pepper on it, tossed on a grate and left alone for hours, can be the best-tasting you have ever eaten.
4.) The range between "perfect" and "awesome tasting" is wide, so don't sweat it, just eat your "mistakes."