Starting with your organic forms with contour lines, these are coming along well. You're doing a good job of sticking closely to the characteristics of simple sausages through the vast majority of these, with only one or two having a bit of pinching through the midsection, or ends of different size. There is one key issue, however: the assignment was to draw organic forms with contour curves, not ellipses. As a result of this, there is one thing that I'm a little unsure of, in regards to the degree of your contour lines, as well as where you've decided to put the smaller ones on the tips of your sausages. It could all be perfectly fine, but the exercise using contour curves helps make issues relating to that easier to identify.

Continuing onto your insect constructions, as a whole you have done a really good job. What stands out is the fact that throughout your work here is that you're clearly thinking about each insect structure as though it exists in three dimensional space, and you are to a great extent treating each individual form as though it is solid and tangible, and not just marks on a flat page.

This is actually the main thing I look for - students at this stage still have a tendency to jump back and forth between working in 3D space, and working in 2D space, often to take shortcuts in adjusting what they've drawn. The issue is that those adjustments occur in 2D space - mainly through modifying the silhouettes of the forms you've already drawn (either by adding flat shapes/partial lines to them, or by cutting back into those silhouettes as shown here). Unfortunately these kinds of actions break the illusion that what we're looking at is 3D. Instead, we have to make sure that everything we add is its own solid, three dimensional, fully enclosed element, and that we're thinking about how they relate to the other forms already present.

Of course, you do an excellent job of this. I can especially see it emphasized in how you wrap the segmentation around the abdomens of insects like your mosquitos and flies.

Now there are some small areas where you jump ahead in the complexity of some elements too quickly, resulting in structures that are too complex to maintain their own illusion of three dimensionality (like this stag beetle's horns and antennae - I'd approach it in stages, building up the basic horn structure then adding its little protrusions one at a time, more similarly to this beetle horn demo), but for the most part you're doing quite well.

I can also see that you were fairly mindful of applying the sausage method to your leg constructions, although you did have a tendency to forget to reinforce the joint between sausages with a contour line (and often put contour lines elsewhere along their lengths). I recommend that you quickly review the notes on that in the sausage method diagram.

I did notice a couple small places where you tried to build upon the sausage structures to build up further detail (like flairing out the ends of a given segment) - in these cases you did kind of fall into the trap of working more in 2D by adding partial shapes and modifying silhouettes. Instead, we can wrap additional masses around the existing structures as shown here. You can also see this in action in this ant leg. The main thing is that we always want to think about how the masses and forms we add to a structure exist as 3D forms (being fully enclosed on their own), and how they relate to the structures they're attaching to.

Anyway, as a whole you're doing a great job. I do want to sort out that contour line issue however, so I am going to assign one more page below, just to ensure that you're not missing something important.

Edit: Oh, I forgot to mention - it's entirely normal for demos to feel easier than drawing from your own reference, simply because reference images are full of all kinds of visual information, and you have to process it to figure out what to actually draw. In the demonstrations, I've already done that processing for you.

Also, most of your construction here (at least any mark that needs to focus on fluidity/smoothness) should still be done from your shoulder. It is definitely difficult, and that's not necessarily how you'll draw outside of the course, but it is to ensure that when you do need to draw from your shoulder later on, you'll be plenty comfortable to do so.