I know exactly what you mean! I always joke that my first year back in shul for more than shofar and yizkor will have to be at a beginners’ minyan. But that’s not much of a joke. The ambience and baal tefillah are something to bear in mind. But assuming you don’t have a choice where to daven, bring a really good machzor, with translation and commentary, like Artscroll, for when your mind starts to wander.
(BTW, made the apple cran crunch. The whole thing looks great but I especially like the crust.)