To get better at setting, all you need is a lot of practice. However, some coaches don't have the time to spend with one individual player since they're the only coach and they need to help everyone out. This is when it hurts the team when the organization doesn't have enough money to hire an assistant coach. Or it hurts even worse when you won't have one step up and volunteer when they see the coach is looking for help.
However, if you really want to impress people with your setting skills, you may want to go to volleyball setter camps because you'll learn more there than you ever will, well depending on the setter camp though. At these setter camps you'll probably go over and over again different volleyball setting drills that will help you out. Also, sometimes colleges or other places will have classes for coaches to learn new things to teach the team. For example, they may show the volleyball coach what they should do when coaching the setter techniques.
Therefore, I would go out and try volleyball setter camps unless you're lucky enough have some USA volleyball player as a coach!