I have been working with some students long distance on critiquing their work, either lesson by lesson or for more finished work. Here is a recent example of how this process goes and the success that is exciting for me to see in their work.
Here is where you can get a detailed critique, lesson by lesson so that you can get an understanding of exactly what you will need to do to improve your drawing techniques step by step.
The lessons are from Wendy's two books:
Botanical Drawing, A Beginner's Guide or
and A Year of Botanical Drawing Subscription Program.