Arrows

They are pretty good and flow pretty nicely. To improve them you could make the growth of the arrows (both the size of the arrow itself and the spaces between folds), to grow more exponentially.

Organic forms

You've a few bulging and others with one size of the form pinching. Remember that the forms should be simple, only 2 balls connected by a tube of consistent width.

You've also got a few problems with the allginment of the ellipse. Remember they should all be alligned to the axis. Corrected a few of the allignments and forms so it was a bit more clear.

There's also the problem that you aren't shifting the degrees of the ellipses, they should shift, even if the sausage was straight, as you can see in this picture, try to be more conscious about it.

Otherwise, lines are confident and pretty accurate, good job!

Textures

On your textures you're doing a pretty good job, you're relying on shadows to draw them, and the gradations from black and towards white are smooth. Dissections wrap nicely around the forms and you are using use of the silhouette to help convey the texture better. There are a few were they could wrap a bit better around the form, but nothing specially wrong.

Form intersections

On your form intersections, you're doing a good job doing confident linework, though I think you might have rushed some of the lines, as they overshoot quite a bit. Remember to always draw starting and ending dots before drawing any line, and to ghost the lines until you're confident.

In all the forms and specially in the boxes, try to mantain a consistent shallow foreshortening instead of a more extreme perspective (which you did specially in the first page).

Be sure you don't repeat any line as well (I saw you repeated a few), even if they're wrong.

Organic intersections

Your organic intersection feel pretty solid in general, but there's a problem, and it's that you aren't drawing through your forms. If you take a look at the demo, you'll see how uncomfortable starts by drawing the sausages completely and separetely, and after it defining the relationships between them.