Yo!

Lines in general: make sure you take your time when placing your pen onto the start point. And for the superimposed lines be mindful of the shape of the initial line.

For boxes, try to not go over a line twice or extend it. Try and do your lines in one go even if they end up looking like crap -- confidence over accuracy for now.

It also looks like you have slight arching when you've gained some speed in your lines. Experiment with slightly arching in the opposite direction when you see that happening.

You should make ellipses a part of your warmup. I suggest the ellipses in planes exercise to hit both the ghosted lines and ellipses muscles.

Feel free to move onto the boxes challenge!