Use added weight, either with a weighted vest, a disc on your back or similar.
Perform push-ups on the ground.
Adjust the weight so that it is demanding but not excessive.
Try to break the ninety degrees when going down and completely lock when going up to perform a complete repetition.
chest · triceps
chest · triceps · legs
fullbody
chest · triceps · shoulders
chest · triceps
chest · triceps · shoulders · core