What can you be doing that is going to benefit you more than what you're doing right now? This is the first concept you learn in economics 101 in college and it lives with me til this day, BUT I haven't used this idea to its fullest until only recently.
I've found that my mind needs CONSTANT stimulation in order for me to not take a nap all day, therefore I'm constantly doing something that can progress a part of my life. At the moment, I work, after work I go to the gym, after the gym I have a few hours at home to unwind.
I work to make money, I work to build a resume, I work to be able to brag to future employers about what I've done.
During work, which isn't that hard, I listen to language audio tracks to learn new languages, I'm on French.
I go to the gym to stay healthy and to stay in good shape, enough said.
At home I've picked some hobbies, one of which is painting, it serves as a form of relaxation and self expression, if I really get into a project 5 hours can go by in a flash, and what do I have to show at the end of it? A new piece of art.
Be sure to challenge yourself everyday, find what you like to do and having a productive day will become second nature.