SLAM magazine's Matt Caputo has a good Q&A with Mark Price, a four-time NBA All-Star who won the 3-Point Shooting Contest twice, in which he asks Price about how he developed as a shooter.
The secret is you have to have good technique and you’ve got to spend the time and put hours and hours in. There is no quick-fix. You hear the term, “pure-shooter,” but what people would call a pure shooter is a guy that’s probably spent a lot of time in the gym working on it.
I spent a lot of time in the gym. I was fortunate because my dad [the late Denny Price] was a coach, and I typically had a place to work out. My dad taught me what he thought was the right way to shoot the ball, and he told me it was up to me as far as how hard I was going to work. I spent a lot of hours just trying to perfect my shot, because I wasn’t real big—I was probably only 5-11, 155 pounds when I showed up at Georgia Tech. I had to work hard on my skills.