Push-ups are commonplace. If you train regularly, chances are you can do multiple in a row. Problem is, most people aren't doing them correctly. And most people never get better even while progressing with other lifts.
Why? Because when you do it right, it feels harder, and you're forced to complete fewer of them. So instead of doing fewer reps with better technique, they rep out with the same flawed form.
There are a lot of biomechanical factors that you have to control when doing the push-up. You press up from a pivot point (your feet) which means your body is following a slight arc. That's important because it tells us where our weight gets shifted as we push up – towards our feet. So, the closer the resistance moves towards the pivot point, the EASIER the rep gets. With that in mind, there's something that'll help you get better.
Make the resistance travel straight up and down by shifting your bodyweight.
Doing this will offset the arc of the weight, keeping the resistance much more vertical over the range of motion.