There are heaps of places online you can look to get drawing tips. Some youtubers I found covering body anatomy stuff are
Draw With Jazza,
Drawing Art Academy, and
Sycra, and that was a 5 minute google search. You can do similar things with anything you're looking to draw really. I'd suggest you start with just getting the basics of drawing a body down, then you can start moving onto the face, and once you've got them down really well, then try for drawing the body in motion. If you've got the basics of drawing a body down really well, you should be able to understand how to draw motion much easier.
Sara Tepes has some good tips as well for improving quickly, although it still all applies for improving at all. Fair warning though, it's a lot of work. Art is a skill, you can't magically get good overnight, so you're going to have to put in a lot of time and practice heaps to improve. The practicing doesn't have to be good, it can be terrible, but as long as you keep drawing, you'll get better.
Mattias Pilhede has some general tips on beginner drawing as well that you might find worthwhile to look into.
Another way I like to improve is to watch speedpaints. Go out, find a drawing that you like, and pay close attention to how the artist draws the picture - you'll pick up on little things as you go, provided you know enough about the medium they're using to understand what's going on. But the important thing to keep in mind with speedpaints is to not compare yourself to that artist, if you can help it. Sure it might seem like they can magically whip up this awesome picture, but you don't know how long they practiced to be able to do that (spoilers: probably years and years of work). So yeah, lot's of practice, learn how to break anatomy down into the basics, and be patient with yourself.
