Re: Scoring Ability
For finishing, use pads, they are so useful. One of the gyms I go to has these different pads designed for football and boxing as well as other sports, basically get a partner and practice finishing with different hits. For example, the linebacker pad can be placed under the basket and you can drive and have your partner hit you with the pad as you go up. The thing weighs like 50lbs so it hits your body pretty hard.
Or using the boxing pad, have him provide constant pushing/bumping until you go up for the layup/shot and then he hits you with it. These all teach you to keep composure after a foul and to finish the shot if the foul isn't called.
For ball handling, contrary to what most people would say, I'd avoid doing the stationary dribbling drills. Not saying that they aren't useful, because they definitely are great ways to improve your dribbling and finger control, but they don't really improve ball handling. There's a difference between dribbling and ball handling, dribbling is how well you can dribble (obviously), and ball handling is how you move the ball and control it in a game situation.
All the stationary dribbling moves don't help you in a game as much as you'd think. Lots of people are good at them but come game time are still turnover prone. Same for me, whenever the defense closes in, my handle gets shaky even though I used to do those drills.
My best advice is to use the full court and have constant pressure. The key to being a good ball handler is to adapt to the worst situation possible, which is major hacking and fouling. Today I did a drill where I had to get into the paint while a defender was hitting me and slapping at my hands and arms. Once you can do that efficiently, pressure won't affect you because you're used to all the hits. So practice taking the ball up and down the court and to various spots while you're being fouled or double teamed or whatever situation you want to recreate.