I would say I still pretty much suck at anatomy, but initially I learned by a) looking at other humans beings (generally advisable) and b) the medical journals in my house. My parents are doctors so I learned to draw hands and feet by looking at the bones. Once you know how something looks on the inside it’s infinitely easier to understand why it looks the way it does on the outside.

Of course, later on I took figure drawing classes and started to really look at how the proportions and muscles work. Figure drawing with a good, patient teacher is the absolute best way to learn how to draw humans.

I made a stream about other generalized anatomy tips over here but again, I am not an expert by any stretch. Best way to get a hang of it is practice practice practice. Not what you want to hear I’m sure, but it’s all you’ll ever hear when you ask, so better to put the hours in practicing than asking.