Do whatever it takes to stay hungry and motivated. This is a tricky art and will require sacrifices. You will have to give up something, whether it be family, money, time, friends, or success. If you want to party every weekend you will have to give up time and money. If you want to be good at a skill then you will have to sacrifice friends and partying.
Motivation can come about in different ways. The people you work with can motivate you to do a better job. They can be entertaining and you enjoy coming into work everyday.
Competition can be motivating. You want to be better than the competition so you work hard and find ways to differentiate yourself.
Significance can be motivating. You want to be the best so you feel important so you find ways to stand out and deliver the best quality you can.
Learning and growth can be motivating. You want to be better than you are now so you do the work to make yourself better.
Love can be motivating. Love is driving you to be better to take care of yourself and your loved ones. It can never get old if you love what you do.