im pretty good at drawing hands without reference! if you want a tip on how to do it the best thing to do is take a photo of your own hand doing the pose (if you cant find any online references for it) and draw it WITHOUT tracing the photo/reference. it wont look very right but eventually you hardwire into your brain how a hand works and it becomes natural surprisingly quickly. this is true for pretty much anything art related id say, but this is a really efficient method for hands especially.
ok brb I'm gonna sell my soul to the devil
edit: the devil told me that they don't want my soul #sad
so my style is mostly very messy and sketchy and im nowhere near professional in my execution But i do think both my hands and feet are good enough to get the point across and therefore a good enough starting point for even more detailed/precise art styles lol.
i dont draw feet nearly as often as hands, but my favourite shortcut for them is this sorta triangle shaped (ankle to heel to bit toe) + the toe shape. from the sole view i usually go this route of circles for the heel, the balls of the foot and the big toe and then kinda bullshitting the arch and the rest of the toes.
as for hands i go largely by feeling, but to get that feeling i think you need to do a lot of observation and studies. once you get used to the most common shapes and angles, you can freehand your way through most gestures, at least for the base sketch. usually i go with a circle/squarish shape for the palm and then two main lines for the pointer finger and the thumb. the rest of the fingers follows in a parabola sorta arch. nails are super useful anchor for perspective and volume of the fingers. if im drawing fingers from perspective i just kinda go for these sausage shapes lmao, when refining those you kinda have to worry about rendering the finger pads just right to really get the correct shape across. and when drawing hand from the thumbs side side view, a similar triangle trick applies (works best of the thumb is pointing away from the palm, just look at your own hand and clamp your thumb in and out, you will see what i mean).
oh and for both, but especially the hands, its important to remember that more often than not you will be looking at the palm and top side at the same time, kinda like if you fold a paper in a gentle arch.
Even with references and practice my hands still come out lookin' like garbage. ;-; I feel like I've personally hit a plateau when it comes to hands.
I honestly find feet easy to draw. Hands are worse. But using refs & taking pics of your own hand works. Just don't trace them. Reference only. That way your brain actually does something which makes it easier over time.
Also, while most of those "don't do this, do that" posts are pretty lame. (Primarily the video types though) Some of them are actually very useful. I browse through Pinterest for this stuff. Since I struggled with finger shape, I found this. Ngl my fingers improved 101% because of that little tip. You can collect a ton of these for all sorts of stuff. Just be sure not too pick too many stylistic stuff. Realism is much better for learning. Otherwise you just copy styles and their errors. Well, unless your style is the exact same, then I guess it somehow could work. But it's still best to learn using realistic images and tips.