Practice.

I used to be able to draw but then I got into photography but just briefly because along came computers. Although I had been drawing a lot and well since before school-age (5 years old) or so my mom says.

Now having been lazy I haven't drawn anything in almost two decades. If I had it and lost it I'm sure I, or anyone, could practice to learn again or as beginner to learn.

It's very zen to do you can't rush it's something you have to slow down to do and learn to love it. It's the only thing where I could really concentrate to the point I'd come out of it (trance?) hours later.