Starting with your organic forms with contour lines, these are generally okay, but I have a few points to mention:

  • Make sure you're sticking to simple sausage forms - avoid having them swell through the midsection, and having ends of different sizes. Also, try to keep the forms more consistent in their volume - avoid the kind of wavy edge we see here. Draw the sausage forms such that they feel more "inflated".

  • It seems to me that you may sometimes be placing sausage forms underneath ones that have already been drawn. If this is the case, don't - always build up. The nature of this exercise is such that we draw the silhouette of each new form so it responds to those upon which it is being dropped. If the form that's meant to be on top has already been drawn, there is no way to make it respond to the new one after the fact. You're effectively cornering yourself in a no-win situation.

  • Make sure your shadows are being cast by a consistent light source - avoid having some shadows cast in one direction, and others in the opposite.

  • Make sure your shadows are actually wrapping around the surface of the forms beneath them, rather than clinging to the one casting them. For example, this form's shadow seems to behave as though it were being cast on a flat surface.

Moving onto your animal constructions, there are definitely some issues here, but they are things we can address. I'll lay out the biggest ones, then we'll have you draw a few more pages and we'll move forward from there.

The first thing that caught my eye is the heavy use of contour lines - specifically where they don't really help all that much. Specifically, you tend to pile them onto additional masses as you've done here. Contour lines like this - the ones that sit on the surface of a single form - will help a form feel more three dimensional on its own, but what matters most with these additional masses is that we establish their relationship in 3D space to the rest of the structure. These kinds of contour lines simply don't help with that, but your approach appears to be more to draw those additional masses first, then worry about making them look 3D.

Instead, leave the contour lines aside for now. Let's think about how these additional masses exist when they're on their own, just floating in the void. Here their silhouette is in its simplest possible state - just a circle, made of outward curves. It is only when we press it up against an existing structure that we start adding complexity to that silhouette, developing more inward curves and corners on the side that makes contact. You can see this demonstrated in this diagram.

The key here is that the shape of your form's silhouette has to directly respond to the forms that are actually present in your construction. We can see that demonstrated here. Note how the top side is kept completely simple, curving outwards, because there is nothing to press in on it.

The next point is simply that you're trying to do far too much with a single additional mass. Looking at the drawing I used above in my demonstration, here you've got a single additional mass extending along the neck and the entirety of the torso. Instead, break it up into a series of separate forms. We actually get a lot of the nuance that implies musculature from how these additional masses actually layer on top of one another. When you try to lump them all together, it all becomes artificially smooth. Here are some additional notes to that point.

Another point I wanted to mention is that I simply don't think you're working as directly from your reference as you should be. There is a lot of oversimplification going on that suggests that you're working more from memory than you may even realize. The vast majority of your time throughout these drawings should be spent studying your reference, observing it directly and only looking away long enough to make a specific mark. At this point, I went to check how long ago you had lesson 4 marked as complete, and rather conveniently it was two weeks to the day, before you submitted this one.

This starts to create a pattern that suggests maybe you didn't really invest as much time as you reasonably could have into each drawing, because perhaps you were working under an artificial deadline, attempting to get your work submitted as soon as you could. Remember - the one thing students are expected to do is to submit work that demonstrates the best of their current ability. One cannot do that if they are rushing. These drawings themselves have no set amount of time they're expected to take. They don't need to be completed in one sitting, or in one day. They simply need to demonstrate to me the best of which you are currently capable, so that my critique can be as effective as possible.

Moving on, while you're headed in the right direction with your head constructions, I suspect that you may not have read through this demonstration from the informal demos page. As I work through countless critiques for students, my strategies for teaching certain concepts evolve, and while I am steadily working my way through updating lesson and video content starting way back at Lesson 1, until then I put more recent strategies in this informal demos section. Be sure to read that explanation, as it goes in-depth in how one should think about applying head construction. When applied to one of your constructions, here's what it would look like.

Lastly, in regards to your use of the sausage method for constructing legs, you are moving in the right direction here, but I'm noticing that there are still cases where you employ ellipses instead of sausage forms. Be sure to always stick to simple sausages for the base construction, then feel free to build upon them as you like with further additional forms.

Now, as I said, I'm going to assign some revisions below. I expect you to invest as much time as you need to execute each to the best of your current ability. That doesn't mean perfect work, or even good work - just that you take the time to observe your references far more carefully, and that you work through the steps of each construction with much more patience.