As you have heard on the other thread, Rescue will likely not improve your own personal diving skills. But you should practice emergency skills in the class, like air-sharing. And Rescue will change the way you think about AVOIDING problems, and recognizing situations that are likely to lead to them. I thought Rescue was the best of the mainstream classes I took.
For development of personal diving skills, you can a) dive with good mentors, b) take "diving lessons" from an instructor who has skills you admire, c) take a recreational class that focuses on those skills, like Fundamentals or UTD Essentials, or d) take a cavern or intro to tech class. You will have to do some significant homework to find an instructor/class in mainstream education that will really polish diving skills.