I've had several smokers; wood fired, electric, charcoal. Never had a gas smoker but I'm tempted to build a multi-fuel smoker out of a huge industrial bladder/surge tank I scavenged.
There is some voodoo involved with rubs, seasonings, braising steps, searing steps, and other processes that affect the outcome, but the smoker itself is a no-brainer. There really isn't anything you have to do except add wood chips and wait.
When you're cooking low and slow, always inform your dinner guests that dinner will be anywhere from 4pm to 7pm. I've gotten pretty good at hitting targets with some maths, but every piece of meat is different. This 10 lb brisket might cook faster than the 9 lber beside it.
It's such a shame that briskets are a fad now. I used to buy them for 99 cents a pound but that was 15 years ago. Briskets are hard to screw up. Season the snot out of them, put them in, and wait for the temp probe to tell you it reached 195. Don't worry about trimming fat caps. 90% of the fat will render out and drip off. Seasoned pros have discovered that very little of the fat in the blubber on top actually goes INTO the meat. Trimming the fat should really only be done so that you have an easier cleanup.... or if you have guests that like eating crusty fat, which I do.
Myths: Searing (reverse or otherwise) seals in juices? It does not. It adds flavor
Resting isn't necessary? It totally is. When it comes off the heat, the juice is hot and looking for a way out. Cutting it to early will just leave all the juice on the plate and not in the meat. Don't underestimate how long. You can let a brisket rest for an hour and it will still be hot enough to serve.
You want a deep smoke ring? You do not. You'll get a ring of some sort, but a big smoke ring means your meat probably tastes like just smoke. Less is more. For a 15 lb brisket I'll make up 4-5 foil packets with a palm-full of chips. I'll put two in to start, then two more after a couple hours, so the smoke part is done before the halfway point.
Tips: Put chips in a foil packet and poke it with a fork. This keeps oxygen away from the chips and forces them to smoke. If you just put soaked chunks or chips on the burner, they will steam first, smoke for a little, and then just catch fire and flame doesn't make smoke.
Use the smoker for the whole meal. Stuff some peppers with bacon, cheese, and cream cheese and put them in for the last hour. Slice some beets and lay them on a rack for a bit. Smoke a head of cabbage and make some slaw. I once tossed a slice of carrot cake in. Aside from the complete mess the icing made, it was pretty good.
Do keep water in the pan. Smoking without that humidity can dry the meat much faster. It also mitigates and re-directs heat. If you don't, the radiant heat from the burner will overcook the bottom. The water also stabilizes the temps, so if you have to open the door to check something or add chips, the big pan of water is like a heat storage device and it will recover faster.
Anticipate the stall. If your smoker is 220 degrees, you can imagine how it will work. The meat will warm up quickly at first and give you the impression that it's going to get done too fast, but as the meat approaches the temp inside the smoker, it slows way down because the temperature difference between the meat and the smoker is much smaller. Don't stress about it or crank up the heat, just wait. Beer or Whiskey makes this anticipation more enjoyable.
Watch youtube videos and reels. They'll walk you through some fun tips, like finishing your brisket in a braise sealed in foil, or injecting a turkey with orange juice. I started watching some reels on FB and every time I got to a BBQ reel, I interacted with it so FB would show me more.
Read up on different woods and how they pair with meats. Mesquite is great for beef, hickory goes well with pork and poultry, fruit woods often go with fish. You can also switch woods in the middle. Last summer I did a brisket and some big salmon fillets. I used a mix of Mesquite and Hickory in the beginning of the smoke, then I wrapped the brisket to braise it and threw on the salmon. I went to the far end of the farm where I knew there was a crabapple tree and ripped off a dead branch to use for smoke on the salmon. But, just like with any other cooking, there aren't any rules. If you like mesquite with your smoked scallops, do it. It's your mouth.