The easiest way to create that effect would be by using the shadows and highlights in your palettes to make some elements look further from the viewer (shadows) or closer (highlights). The elbow would be the part of the arm that's the furthest away from her body and ourselves, so it would have the darkest shadows. You can then use the lightest shades in the areas closer to her body: her shoulder, forearm etc. Try to emphasise her elbow with your shadows.
As for the top, I'd say the biggest issue I see with your doll is what I've come to find in most people's work: there's no real volume to your shading. To put it into simpler terms, you seem to think of lines on a screen instead of a 3D body, which may explain why you couldn't figure out the foreshortened arm: because that requires thinking in three dimensions instead of two. The main problem with how you've shaded her top is that that big shadow to our left makes it look flat. Look at it. You have all that space that is right there in the open, and it's covered by a block of dark pixels. If you think about the shapes in a human torso, you will realise that there should be some shading to convey its natural roundness.
Simply add more shading to it. Take that nice orange you've picked to soften the darkest shadows and extend the shapes in her body to her left. Add some folds near the breasts that show how the top is slightly stretched, or the outter curves of her right (our left) boob. Add some highlights in a softer light to her back (the bit that's visible through her bent arm) to make it look more 3D. I did that by picking the background colour you've used and adding some light orange to it. Simply pick the colours closest to that area and desaturate and cool them down a bit. You can pick some desaturated orange, greys or blues and purples. If you add that cool highlight, you will need to do the same to the rest of the doll, so keep it in mind when making your decision.
As for her feet, body weight is key here. There are tutorials dealing with this that will do a much better job at explaining the technicalities -- Warren Louw's Strike a pose
or Zoe Hong's How to draw fashion figures
series come to mind--, but the basics are as follows: where's all her body weight resting on? One leg? Both? Is it centred? Moved to one side? From the looks of it, her weight seems to rest on both legs, although most of it seems to be concentrated on her right (our left leg). I would show that by making sure her right foot looks firm, secure on the ground. When you stand in poses like this one you'll notice that your foot tends to stick out a bit, pointing slightly outwards. Let's take a look at this reference
. Notice how her right foot (our left) is turned slightly outward and how we can see part of the heel (not the shoe's, but her foot's). Adding that detail will make the foot look more secure, as if it were resting on the ground holding her weight. The shoe's sole will rest flat against the ground. If she's wearing platform shoes, then you'll have the bottom part of the platform rest flat, but depending on the kind of shoe, you may see the tip curve up a bit. In that case, the widest part of the platform (the one with the biggest surface) will be pressed down against the floor. This is because we balance our weight on the foot's sole (widest surface) and not our toes (the tip of the shoe).
Her other foot still carries some of her weight, but the pressure in it will be lighter, so you can have it posed in a different way. I went for a 3/4 view in the opposite direction. That way the weight is balanced between the two feet. If you want to be creative with it, try out the poses first and focus on where your weight falls. Focus on where you put the biggest pressure when you move your body. That will signal where your weight is resting. Just be careful and don't do it where people can see you. They will think you're crazy. Or dancing. Or dancing like crazy.
I've also reshaded her legs, mostly to help the pose read better. Adding some muscle definition* here and there helps people see what's going on with the pose, and your doll looks more like a real human and less like a bunch of pixels. I also added a bit of the reflective light colours here and there to soften my shading.
*You may think this means you have to reshade everything, but it doesn't. You can get away by going over your existing shading and simply adding some shades that add some perspective to your shapes. I'm not sure how you shade: whether you block in the shades or you simply draw some outlines and then fill. But I would suggest that you use a pencil that's bigger than one pixel and add the shadows and highlights focusing on where the different muscles and bones are in a human body. Grab some references and simply see where the main highlights are. The more you do this, the easier it becomes. Learn to read shapes in real human beings and you'll see where to place them in your dolls much more clearly.
- Shadows help make stuff look further away. Highlights bring stuff closer to the viewer.
- Highlights and reflective light make things look 3D.
- Body weight can help you find your feet. Don't let the base's outlines limit you. If you need to edit the whole leg, do it.
- Muscle definition will be your best friend. And it makes dolls look sexy.