Assume a shoulder width hand plank position where the hands are slightly externally rotated driving the elbows close to the body.
Start with protracted scapula, think shooting the upper back like a cat.
When you descend make sure that the back does not shift angle.
When you push your way up do not snake or worm yourself up. This is compensating the movement and you will not develop the strength you seek.
If this is too challenging then instead perform a pushup on for instance 25cm deficit made by weight plates.