1. Practice the take off.
2. Possibly consider Creatine, though it's not necessarily going to work too well.
3. Maybe consider a new pair of Basketball shoes.
4. As for workout, consider doing a total body workout 3 days a week, every other day. Compound exercises, mixed with some stuff four Arms and shoulders. Don't exercise longer than 1hour 10 minutes.
Start of very light, doing 2 sets per exercise with about 8-10 reps. Increase weight a bit more per week, by weeks 4-6, consider increasing intensity or number of sets.
Try this schedule if possible.
Day 1. Weights
Day 2. BB practice
Day 3. Weights
Day 4. Day off.
Day 5. BB practice
Day 6. Weights.
This stops you training more than 3 days stright and gives you adequate recovery, without the off days back to back, eating into progress.