There are a few things you can do in order to improve your chances of achieving a perfect 99 overall in NBA 2K16 for PlayStation 4. First, make sure you have an accurate and up-to-date basketball career. This will help you get an accurate sense of your skills and progress as you play the game. Additionally, make sure you are playing as many games as possible to increase your overall rating. Playing against other players online is also a great way to improve your ranking and stats. Finally, make sure you take care of your health by practicing regularly and eating healthy foods to maintain your health.