1:05 AM, Sunday February 9th 2020
Starting with your arrows, these are generally pretty well done. There are a few where the compression of positive/negative space isn't entirely consistent (positive space being the width of the ribbon, negative space being the distances between those zigzagging sections - perspective applies to both of these equally), so continuing to keep that in mind should help develop your ability to capture depth within the scene.
Looking at your leaves, these do flow quite nicely through space, but a key issue that stands out to me is that you're approaching these like a loose sketch. Your lines are drawn by instinct and reflex, and you're thinking right there on the page rather than demonstrating the kind of pre-planning that is embodied in the ghosting method. Instead of thinking in terms of drawing three dimensional forms in a 3D world (and cutting away from or adding to those forms, again in 3D space), you're very much putting marks down such that you're only thinking about drawing lines on a flat page. For example, if we look at the leaf towards the top left of the page, you've added these little marks along the edge that don't connect to anything. So those lines were not drawn with the intent of enclosing areas of space - they're just floating, independent entities.
The problem comes down to this: you're not drawing, you're sketching.
Moving onto your branches, things get a little better. You're drawing (mostly) in distinct strokes, each with their own specific goal. There's one spot (towards the end of the branch on the middle of the page) where you follow up with an additional stroke on either side, but the rest are single marks. Now, they are still somewhat rushed in a few places, where you either don't extend the previous segment halfway towards the next ellipse, or where the next segment doesn't quite start on the previous ellipse. Both of these end up limiting how much actual overlap you have between segments, and limit your ability to have them flow seamlessly from one to the other. When doing this exercise in the future, I recommend that you make a point of using the last chunk of the previous segment as a 'runway', overlapping it directly before shooting off towards the next goal.
Moving onto your plant constructions, I think the things you're trying to accomplish - in terms of the forms you're aiming to draw - you're demonstrating a good grasp of the overall concepts involved in constructional drawing. Where you're losing touch is, aside from the sketching vs. drawing I addressed earlier, in the underlying principles of construction and how you're building a strict scaffolding, and adhering to that scaffolding as you build out your object in successive phases.
Your construction instead tends to be quite loose. You'll put down a structural element - like say, in page 6 (the sunflower), you may put down an ellipse that is intended to determine how far out the petals extend. Then, instead of actually extending the petals out to that specific distance, so the ends of the petals' flow lines touch the ellipse you'd drawn, you make it more loose and approximate, using that ellipse as more of a suggestion.
In construction, there is no looseness, there is no approximation. Every mark we put down is an assertion - a decision made. And every time we take a decision and ignore it, we introduce a new answer to the given question, and in doing so, introduce contradictions. Like when telling a lie, we undermine the viewer's suspension of disbelief with every contradiction that is introduced.
Looking at the leaves for that same sunflower, here you've skipped steps - introducing more complex edge detail (with slight ripples) - without constructing a simpler leaf form first.
Another issue I noticed is that you have a tendency to try and hide your mistakes by creating larger areas black ink, as seen along the top leaf of the pitcher plant. That big chunk of black along the underside isn't a cast shadow, because it's not being cast onto an underlying surface. It sticks to the form that presumes to "cast" it. Instead, it's just an unseemly chunk of line weight.
Ultimately, you shouldn't be trying to correct your mistakes at all. Doing so just emphasizes those areas by piling on more ink. In turn, this results in the focal points that draw the viewer's eye being determined by where you mess up, rather than how you actually intend to steer the viewer's eyes.
Now, I've said a lot here, so I'll leave you to absorb it all. The key thing here you need to keep in mind is that each and every one of these drawings is intended to be an exercise. We're not here to create pretty drawings, to impress people with how well we can capture something by being sketchy and erratic. Each one is an exercise to develop your understanding of how forms exist in space, how they relate to one another, and how one can combine them to create more complex objects. Remember this goal, and don't allow the desire to create impressive drawings distract you from it.
Next Steps:
I'd like to see the following:
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2 pages of leaves
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5 pages of plant drawings.
No sketching, no loose drawings. Adhere strictly to each and every phase of construction you put down. Treat your marks as decisions being made, not as loose suggestions. You're not drawing lines on a page, you're constructing forms within 3D space.