The proper pushup is hard, and is probably just as difficult as a deadlift to master. But, let’s move forward and help cure your muscular imbalances and strive to produce a sweet looking push-up and/or the nicest progression that will build your strength and stability without compromising your shoulders. Let's build the upper body and torso strength and gain the ability to move our bodies as a global unit. Think of the pushup like a moving plank. https://youtu.be/0gz_w_WY2Eo
Know the importance of bracing your core - squeeze your butt and flex you abs. Keep your ribcage down(serratus firing). This will get your pelvis and midline into the proper position. Also keep your head neutral and your legs locked and together like a good gymnast. These positions carry over to others and will help you with a bunch of other movements in our repertoire towards building better moving bodies. Your hands should be right underneath your shoulders with no more than maybe a couple fingers outside the width of your shoulders. So master it and move on to a happier place.