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Ouch. This is gonna take some work. First off, I recommend you find some tutorials and study 3-point perspective. Which is trickier to pull off than 2-point perspective, though understanding 2-point perspective is the groundwork for 3-point and forced-perspective work.

Before I get going, you realize you're gonna have to at least make some serious changes? I might recommend starting with drawing a box or 'cage' in the perspective that you want, and then filling it in with the subject, so their feet stand flat on the bottom of the box lining conforming to those perspective lines and the shoulders or head lining up with the top of the box.

As an aside, once you have the box in perspective, you can segment it easily. The center of any square, even on in perspective can be found by drawing diagonals, from one corner to the other to form an 'X', the center of which is where the midpoint of the square lies. This will help you segment the upper body and the lower body accurately, and can further segment to place the knees and chest if you're using something akin to an 8-head model approach.

If you're short on time, overwhelmed, lazy, freaked out, whatever, get a piece of paper and start tracing the basic form of your current drawing making alterations to the perspective of the anatomy till something looks better. For example, try placing her right foot where her right knee currently is and redraw the leg in the new position. Or take the shoulders, make them the top of a box, draw the box in relatively accurate perspective and then place the feet.

Right now the legs on the shorts are the exact same length. With one knee up and the other straight, a difference in the length of the shorts would be seen. And her hips should probably be thinner to conform to perspective and her legs as a whole, much smaller. Her right forearm should recede much further, too. At present the right humerus (upper arm) is a bit short for how it's depicted. The left humerus should also be much longer than the ulna & radius (lower arm) of said arm.

In terms of staging, you're lacking an easily read silhouette with her left leg up like that, combined with the striped stocking and conformity of line-weight, it doesn't read well at all and confuses the eye so much that it takes too long to figure out. So the drawing becomes a drawing about her left knee, not what she's shushing about.
Changing the thickness of the lines used in the depiction will also help structure the perspective, overlapping and distancing that appear in the anatomy.

Those are the main talking points I thought I should hit. sweatdrop

That is extremely helpful. Thanks! I can see this does need a lot of work. Don't know if I'll come back to it or if I'll just start something new, but I'll keep what you said in mind when I try this again. I'd never thought to just use boxes before, but that's like the most amazing thing ever now that I think about it, haha.