I find this a difficult question because you do want to be called by your proper name and pronouns, but, as you say, you don't want to come across as a jerk. Depending on how you go about it, people can react very badly.
Once when I was at the butcher's, the guy called me by my old name and rather loudly, too. Fortunately, there weren't any other customers within earshot or it could have been very embarrassing. A couple of days later I managed to get the guy on his own and had a word with him. At first he denied that he had called me by the wrong name, and then later, in a roundabout fashion, he admitted that he had. I took the approach, "Sometimes people just slip up, no big deal, but I do like to be called by my proper name." That is, I didn't come on too aggressively. He took it well, and he hasn't slipped up since.
I think you need to tailor your approach to each individual. Circumstances, and hence necessary action, can vary. Those who've known you the longest and best will perhaps have to most trouble switching over. With them you may need to give it some time.
It's a nuisance, but I think patience is required because people can react badly if they don't like the way you're going about it. That's not really fair since they're the ones in the wrong, but you do want to retain people's good-will--even if they're making it hard on you.
