Overall there's definitely a lot of good exploration being done here, and I can see you attempting to apply the principles from the lesson in a variety of ways. That said, one thing that is holding you back is that you're rather sloppy when it comes to application of the more basic elements - like the execution of individual marks, the use of contour lines, etc. and it shows that while you're approaching things reasonably well in terms of the big picture of your constructions, you aren't investing as much time as each individual mark demands.

You did mention that you tried to apply the ghosting method to each and every line and to draw from your shoulder, but that is certainly left up to interpretation. I try not to work off what students self-report, and focus instead entirely on what the drawings themselves tell me. One quick example is to look at the tail on the squirrel on the left side of this page. The contour lines are quite sloppy, and do not show much effort being put into following the trajectory required for each mark to wrap around this three dimensional form. We can see similar issues in the head of the horse on the left side of this page. It definitely wasn't constructed as thoroughly as it should have been, and those contour lines are afterthoughts at best.

In general, you have a pretty heavy overuse of contour lines in general. This isn't an uncommon mistake - it usually suggests that students aren't necessarily thinking about what they want to get out of their contour lines, and how each contour line is meant to contribute to the drawing overall. It just shows that they understand that this tool exists in their toolbox, and so they feel they're expected to use it.

The thing about contour lines is that they suffer from diminishing returns. The first one you add to a drawing may have a considerable impact to make it feel solid and three dimensional (assuming it's drawn well). The second may have far less of an impact, and the third even less. Therefore covering a form in contour lines won't actually accomplish much, but what it will likely do is cause one to put less thought into other aspects of that form - for example, how its silhouette has been drawn, how its relationships with neighbour forms are defined, etc.

Those contour lines that sit along the surface of a single form (like in the organic forms with contour lines exercise), though very useful, are actually not a tool you're going to need to use as often as you might think. What we accomplish by defining the intersections/relationships between forms (which actually relies on a different, far more effective kind of contour line that sits on two forms simultaneously), and what we achieve in the specific shape of the form's silhouette, will often convey enough about how that form exists in 3D space before any other contour lines need to be added.

The key to keep our forms feeling solid and three dimensional without even needing further contour lines falls primarily in ensuring that the forms we build up are simple, and that if their silhouettes include any complexity, it is caused by them interacting with other parts of the existing structure. So, for example, if we look at the goose on the right side of this page, its beak has a bump on it that should not have been incorporated into the first form you laid down for that part of the construction. You should have kept the beak as simple as possible, then built the bump on top of it with another, separate simple form.

It is also important that we draw every new addition to a construction as its own complete three dimensional form. Take a look at this fox. I've marked out two forms with red hatching that were added only by drawing a single stroke that bridged across from one mass to another. This relied on other parts of the existing structure to enclose itself, and when viewed in isolation would not produce a solid, three dimensional form of its own. Make sure that everything you add is a solid, complete, three dimensional form, and think about how it is going to interact with and relate to the structure that is already present.

Looking at the dog on the bottom of the same page as the fox, much of this construction was actually handled really well, but I noticed one key issue - you drew the initial masses - the ribcage and pelvis - far more faintly than all those that followed, and their relationship with the forms that followed seemed kind of... loose. Remember above all that if you allow yourself to approach your drawings as just drawings - that is, something where we have the freedom to make any mark we like - you will be communicating to the viewer the whole way through that what they're looking at is a drawing. In this case, it was just an isolated mistake in the relationship between the ribcage/pelvis and the torso itself. Because the relationship was loose, it doesn't feel like they exist together in 3D space. Make sure that all your defined relationships are tight, with no arbitrary spaces between forms, no random gaps, etc. This goes back to the previous point - if you wanted to add a little bump in an area, that would be a separate phase of construction, added by introducing an entirely separate 3D form to represent that bump - not just a little change in the base form's silhouette.

Getting into those additional masses, they rely really heavily on how their silhouettes are drawn. When floating in the void, we can think of them like soft balls of meat, with nothing but simple, outward curves the whole way through (looking kind of like a sphere). Once they press up against a structure however, the part that makes contact will curve inward in response, and corners will form where these curvatures change. You can see this demonstrated here. These inward curves and corners introduce complexity to our silhouette, and so in order for the form to continue to feel solid and three dimensional, it is critical that every bit of complexity corresponds to a specific defined stimulus. There should be no such complexity without a clear form-interaction to cause it.

For example, looking at the fox on the top of this page again, the masses along its back have inward curves along their bottom edges, but there's no clear structure that they're pressing agianst. Logically it might achieve that kind of curvature by pressing against the big thigh mass, or the big shoulder mass, but neither of these have been defined in your drawing so it just seems arbitrary and made-up.

A good example of how all these forms play off one another can be seen in this ant leg demo and this dog leg demo. You can see there how each form is pressing up against another, how they're all tightly bound to one another, and how no complexity is arbitrary.

I actually did provide you with these demos in my last critique, of your lesson 4 work, when pointing out that you did not consistently utilize the sausage method when constructing your legs. You appear to have made the same mistake here, as most of your legs do not use the sausage method, despite this. I strongly recommend you go back and review the feedback I gave you there.

Now, this critique has gotten quite long, so I'm going to cut it short here, but I will point you to this head construction explanation, since I didn't have room to get into it further here. I'm going to assign some additional pages of animal constructions below.