I start by doing "yoga" of sorts in my bed. Then I visualize what has to happen before I leave the door. Then at some point I do it.
Helps that I usually do things at night that I'll need in the morning. Pick and set my clothes, get a quick breakfast set up, make sure my phone is charging. Most importantly, anything that might cause anxiety is either taken care of, or if it can't be, assigned lower on the list of my worries.