Welcome to Gaia! ::

I can't really consider the second drawing part of your "skill level" because it's copied from another drawing. It's best to stay away from eyeballing/copying/tracing for now. If you want to become a better artist, you need to start drawing with your own skills and imagination.

Anyway, if you want to start getting into drawing poses, you first need to draw more full-bodies. The leap is tough, I know, but only drawing bust shots isn't going to help. Couple drawings are incredibly tricky because it requires full working knowledge of drawing a body in any pose or angle, and then having it interact with another body. When you get the hang of drawing the human figure really well, you can move on to couples with not much problem.

I would suggest that you work on the following before anything else:
*full body pose
*darkening your lines

all your samples were very difficult to see comparable to other sketches.
might I suggest going over them again with a pen.

as for poses,for you I would recommend going over online sites which provide human poses until you get the hang of it.or alternatively buy yourself
a small pose doll,they usually run for 6-20 bucks depending on size.also I key point to remember is that the best reference you have is your own body.
it shows you how far the body can stretch.

In my opinion,body poses are essential before you can move on giving your drawing's clothes the proper wrinkles.

I will be using my own example here so I have to disagree with something that has been suggested.

True that drawing without copying from others is great for experiences in the long run, but in my case, I didn't present any progress until I started copying someone else's work (Well known and complicated pieces) so I could have a better grasp of the idea behind it.

Later after that I slowly moved on and started working on my own style and it was in this stage that I first started using skeletons and stick figures to make a drawing.

These 2 help a lot with anatomy....erm....I better explain that with a small tutorial, but don't expect much as it will be my first real tutorial. ._.

I really agree with these two, not just for the points they've made, but also, somewhere down along the line if you force yourself into a specific style, i.e, anime, you end up kicking yourself. It sounds crazy, but anatomy lessons are great because then you can change it to how you want and it'll still make sense.
Not to say anime-styles aren't great, but there's a whole variety and often I look at western animation styles, and think "My, how similar" and am naturally drawn to it.
However, the greatest tip I can give you about drawing bodies, is to just draw them. Don't focus on the head, just focus on the body and remember, shoulder is equal to hips, and legs aren't actually that long. As for Chibis, all things change when drawing the because they're just that "super deformed" so you can really play around with them. However, I would heavily suggest to keep it simple, so no ultra details on hair (Unless of course, that's what you're aiming for).
Aside from that, good work on it.