Many people work very hard to get their first promotion and then they start losing track of their goal and become happy with their normal performance. But when it comes to excellence, we need to realize that it is not a destination, but a continuing journey.
Yes , if you want to continue getting better rating from your boss(es), and continue getting promoted regularly, you need to continuously enhance your capabilities and also apply them for improving your performance.
Only when you keep on excelling year after year, your boss will be convinced of the need to pay your more bonus and give your better promotion. Anytime you stop losing this focus, and start being happy with what you have so far achieved, then your stagnation starts, and over a period of time, you may be even losing your value for the organization.