Consistency and discipline. Those two things are what get me out of bed at 4AM each day. They make it feel easier over time, some days easier than others. But even with consistency and discipline I have mornings where the alarms rips me from sleep and I feel a little groggy and lost, but the difference is my muscle memory picks me up and starts my mornings in motion regardless of how I'm feeling. Do it enough, it becomes habitual. You can train yourself to do anything you want with enough consistency and discipline.