Agree with the other posters – it’s practise makes perfect with BBQing.
Me and the missus BBQ 3 or 4 times a week during the summer (sometimes more – twice a day at weekends). Gas during the week, then sometimes the smoker one day at the weekend. Do a lot of veggies on the BBQ too so it’s not just meat. We both come from families that BBQ regularly.
Smoked a pork shoulder today, took 9 hours. Am slicing it so I have sandwiches for the week. Yum!
I use a digital thermometer, always for smoking but sometimes for grilling too. Stuff I cook all the time I don’t need the thermometer. Steaks are a good example – sirloins from a supermarket I can judge myself, but if I get a really thick one (did a flat-iron last week) it’s harder to judge because I do them less frequently.