The other major part to MyCareer is the Training and Skills development section. Essentially, when your player isn't hard at work on the court, he should be increasing his stats so that the next time he is called into action, improvements have been made. The game gives you a variety of developmental tools to play around with in order to make your pro a more accomplished player.
There are a total of nine skill drills to perform, and another nine training regimes, bundled up and called 'Legends Training Camps'. These camps improve your attributes through completing them, so are definitely work taking part in. The Skill Drills meanwhile are primarily there to earn VC while not playing any matches. If you have to the time, you should definitely try to do as many skill drills and certainly take part in all of the Training Camps.
To stop people from taking advantage, you can only do a total of three skill drills each week and two Legendary Training Camps every season. This is obviously to prevent anyone from making uber-powerful players by spamming Training Camps. Because you are limited to two each season, you should try to at least maximize those so that you are getting your full allocation of stats increases every year. Actually taking part in the Training Camps costs a lot of VC, so you may not feel it is worthwhile - but it can be a good way to give your character a boost - you're effectively paying for a stats increase using VC.
The skill drills are centered on one of three areas. These can be Offense, Fundamentals and Combination. You can choose whichever one you like of these based on your preference. The idea should generally be to pick whichever one you're best at, unless you're getting bored of them. This is because your performance in the Skill Drills reflects directly on the VC that you receive for completing them. There are three tiers of reward on offer - you are aiming, fairly obviously, for the gold rating.
TIP: Some Drills are harder than other, so just repeat what you know works to get the most VC for your time.