I see you are definitely moving in the right direction here, the additional masses are pretty well done even when you are not using any contour lines, and also they don't have any arbitrary corners which is good. In your first drawing I like how you used shoulder and hip masses to provide with some additional structure to push the mass against and make it feel more grounded. Always strive to do this when drawing quadrupeds.

Regarding your legs, you are clearly sticking to the sausage method and its requirements, but remember to highlight the intersection between forms with a contour line, always.

Regarding the head construction, apply the approach that I put above, try to do it directly - down to even the specific eye socket shape of a pentagon with a point facing downwards. This allows for the muzzle to fit in the resulting wedge between the sockets, and for the brow ridge/forehead to rest on the flat surface along the top. I don't put too much stress on this as you are already moving in the right direction here.

Your observational skills are excellent - just make sure that you're investing time into understanding how the forms you identify exist in 3D space, so you can build them back up using construction, rather than purely observing and transferring what you've seen to the 2D page.

So I'm pretty sure you can move, you have showed a good deal of understanding of the concepts in this lesson.