I don't know what exactly people consider great bbq, but I know what I like and my friends seem to like it also.
Everything I really know about bbq, I have learned from countless hours here on the forums and cooking bbq 2-4 times a week (year round) since I started on this hobby/obsession/whateveryouwanttocallit.
If you are not sure what a good rub means to you, try a few commercial rubs to find out what you like. Some great commercial rubs are Plowboys Yardbird, All of the Simply Marvelous likes (I suggest you get the sampler pack to try them all!) BigButz Cow Pow and Pig Pollen, and I'm sure other people on the forums will tell you others they found to be good.
What I did when I started was use a commercial rub to find out what flavor profiles you do like. You can work on your technique more this way instead of stressing about another factor. Once I got my techniques down (knowing the feel of the meats when they are done, hot and fast vs low and slow, etc) I started messing with homemade rubs. I started simple with Salt and Pepper and have added and subtracted different herbs/spices out of the equation.
I have now started messing with injections to see how that changes the flavor profile/texture of the meats and to see if I like what they bring to backyard bbq cooking (as opposed to competition one bite cooking).
If you are into the hobby/obsession of bbq, you have to have patience. And learn different things throughout your journey. When you start it, go simple and grow your knowledge and techniques more and more. After a bunch of cooks you will find have points that where your eyes open much wider and you realize, damn what I have been working at, I just nailed and it will be much easier to get to that point.
P.S. Also another way to improve is to keep notes on all of your cooks. That way you know how much of each ingredient, time between rub to smoker, how long before you wrapped vs no wrapping and you will be a much better cook for it.
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