I've been doing early am workouts for the past 100 days or so. The transition was easier than I expected with a couple of personal tweaks.
1) I don't go to bed before tangibly thinking to myself I am waking up at 0345 or 0400. That way there is no option for me to sleep in or snooze. Its amazing on days where I "wait and decide" when I wake up that 95% of the time I sleep in.
2) I think I got this idea off this site but I set my alarm 15-20 minutes earlier than necessary and take a fat burner or chug preworkout and lay back down. Usually the placebo effect or actual effect gets me up and ready by the time I need to physically get out of bed.
3) Loud Music on the Drive. Become a psychopath. I yell lyrics. Rap a fast song. Whatever it takes. It's cliche but I sorta feed off the fact the rest of the world is asleep and Im blasting slipknot.
4) I generally start slow with abs or a basic accessory exercise to get me "awake". If you have enough time, I'd recommend eating something prior to the workout that way your natural instincts to quit working and seek out food dont kick in.
Just my two cents. I'm not Ronnie Coleman by any means but I've gotten into this routine without suffering a lack of intensity that I expected.