All pushups are not created equal. I learned this while researching an improved exercise routine. The pushups which I thought were acceptable are evidently absolute garbage. After learning correct form, I was unable to complete one.
A reader linked me to a recommended routine at Reddit. I generally trust Reddit, so I gave it a whirl. It is a little bit tedious and complicated, but so are many tasks that are worth the effort. If I stick with it, it will become easier in time. I will be doing this routine three days a week. It seems intelligent and complete.
Each part of the routine has "progressions" - or different versions of the exercise which increase the difficulty. So the routine will work as you get stronger. It will work for anybody from novice to superhero. I look forward to being less weak.
Today I did pushups with perfect form. I could only do five at a time, in spite of pushing up from a fairly large log. This made me feel silly, but I could shrug that away. It beats getting wasted and falling asleep in direct sun - and there's plenty of that going around.