Start in a plank position with your arms and legs straight, shoulders above your wrists, and two yoga blocks stacked vertically underneath your chest.
Take a breath in, and as you exhale, bend your elbows out to the sides and lower your chest toward the ground. Stop as soon as your chest touches the yoga blocks. Inhale to straighten the arms. This counts as one rep.
If this is too difficult, do this exercise with your knees on the floor.
As you continue to get stronger, remove a yoga block to increase the depth of the push-up. Eventually you'll be able to work your way up to doing a push-up without a yoga block.