7:35 AM, Wednesday August 12th 2020
Hey! It's really nice that you've revised your work.
I can see you've put more thoughts into leaves exercise. They look more dynamic, showing both the top and the bottom planes.
I think twisting leaves are not an issue, but having control over when you would like it to twist and when you wouldn't want it to twist is the key here.
I think of the line going from the base of the leaf to the tip of the leaf as vertical axis, and I use imaginary lines perpendicular to that axis as my guide to determine which way the plane of the leaf is facing.
It's a bit hard for me to explain how I think about this... so please refer to images below, and see if they make sense to you:
Your 3D arrows were very well done in the first submission, so I have a feeling you'd have a lot easier time imagining the leaves initially as rectangular planes.
I use shading that follows the direction of my perpendicular guidelines mentioned above... somehow it makes sense to me, but I don't think there is a fixed rules for how you can shade the underside of the leaves.
As for the branches... to be honest, I draw a single continuous line after I draw the ellipses along the central axis... I tried doing overlapping lines, but like you, my lines don't seem to overlap well and they don't look very smooth :-( So... I'm not sure how to advice you on this. One thing I can say is that I do the ghosting lines for my one-stroke curves to make sure it touches the edges of all ellipses.
Next Steps:
Feel free to repeat any of the exercises, but you don't have to aim for perfection!
Learning to draw is a life-long process. You will learn a lot by trying to draw seemingly unrelated things, so go ahead to later lessons if you haven't already done so :) Happy drawing!