To me, "flying well" just means "don't **** up too much". Don't joust with a list that you shouldn't, don't slap into rocks/ships, that sorta thing. Sure, there's another layer of skill that can come into X-Wing, but learning the absolute basics of flying are the far more critical. All of the "beyond beginner mistakes" you list are, comparatively, less critical than the basics that come before. Obviously you still want to learn that stuff, but the biggest, most important step will actually be knowing how to fly the ships in your list: staying in formation (or out of formation if you have a LW flanker), not costing yourself wasted actions/dice modifications/attacks.
Because nothing will sink a player faster than having ships getting attacked without attacking back, or not being able to modify your dice. Indeed, a lot of the time I see dice get blamed is when a player isn't getting modifications. If anything, you should thank the dice for when they do roll well without modifiers.