Hey, Jackc! Here is my critique, I hope it will be helpful to you!

Organic Arrows

These are pretty good, but you can improve the shading. Specifically, it looks out of control. You want to convey the surface as well as the shadows. Keep the hatching lines parallel, going across the surface (see the shading lines here).

The Leaves Exercise

Nice work with the compound leaves and edge detail! I see you made some mistakes, but you corrected yourself, good job! Concerning the shadows/texture, you might want to avoid “scratches” like in the leaves at the bottom of the page; better use the texture like in the leaves in the middle.

Another, maybe counter-intuitive idea, might be to texturize the light areas since light gives more information. This can make your drawings “pop out” even more.

The Branches Exercise

Although most of your lines are confident, I can see fraying and double strokes, almost as if you used a pencil and erased it later. Don’t worry if a line goes wrong. Don’t redo the line - try to work around it. It’s a valuable skill, especially later on when things get much more complex. I am glad to see that you passed each ellipse twice, and really tried to align everything to the axis. However, you can make this even better by changing the degrees of your ellipses.

Plants

First off, nice work, and well done with applying what you’ve learned in the Leaves and Branches exercises. Your plants look three dimensional and I can see you thought about the forms that make them up. Keep this up! You have the required number of constructions as well.

I noticed that some of your mushrooms have very “frayed” ellipses – did you go over them more than three times? Maybe your fineliner stopped working? Anyway, go over the ellipses 3 times max, and other lines and curves only once.

Concerning texture, most of it is pretty good. You might want to avoid lines such as those on this mushroom. At least make them thicker on the darker end, just like with the gradient in Lesson 2.

That’s it! Nice work!