[John Izzo]

Here is the progression I use with clients:
1.) Push up against wall (body at slight angle)
2.) FLoor push-ups with modified lever (knees bent)
3.) Push-up agsinst smith bar/bench/object
4.) Push-up planks Hold (10-30 sec.)
5.) Push-ups

Amount of time it takes to get to a standard push up depeneds on individual.

AUXILLIARY Exercises to Hlep
1.) Scap Press
2.) Planks
3.) Bird Dogs
4.) Any upperbody weightlifting

I think hip flexor involvement is most seen when people tend to push their buts up in the air when pushing up.