These are really excellent drawings Jessica. Great work! My comments are very general so I won't use my red and blue markers.
My favorite part of your drawings is I can still see your construction lines. It shows that you built the drawing from the ground up. It makes the final image feel like it's truly leaning on that underlying structure.
If there's anything to improve it's in your line work. Your lines are very confident (meaning you're sure of yourself and your ability) but your lines could be even more confident. And that really just comes with lot's of practice. The more you draw the more you'll be sure that the strokes of your pencil or pen are accomplishing exactly what you want them to. Until then - keep exploring and practicing.
Thanks Jessica!