You have quite a bit of fraying on SuperImposed Lines exercises. Make sure your pen is situated within the same point. All it takes is a little extra time and this will improve your work on all other exercises. Your lines are very smooth, though!

This doesn't exactly pertain to any one exercise, but to all of your work. Try to make your goal points for each line a bit smaller. It is difficult to determine exactly where you want your line to go both when making a mark and afterwards when you are analyzing your work. The smaller these points are, the better you can see where you need improvement.

Ellipses: I can't exactly tell how fast you are making your marks, but my best guess is that you are going too fast. It is important to get fluid lines that don't wobble, but you do still have goals to meet. You want to mark through ellipses as closely to your original loop and you want to meet the guidelines. You need time to process the action. Experiment with how fast or slow you make your marks. Find the balance where you have control and smooth lines.