So, I remember being at this point myself. I had not done a lot of gestures or quick study drawings and I was struggling to understand. There is a gob of information to process and in my case, I was having a hard time understanding. Things I found out by practicing with professional artists: #01. I was actually doing better than I thought I was doing. It was nice to watch a pro make some incredible art, and even nicer to see that they had drawings where they struggled too. #02. The purpose of doing very fast gesture drawings is to train your eye to find the largest line/lines of action AND to loosen up. More important than volume or proportion, you are looking to express the activity as clearly as possible. This means that you spend most of your time capturing the line of action. Focus on that. I normally have to draw two, three, or four lines to capture the action, then I reinforce those lines with long, flowing lines. Don't worry about putting in all of the pieces. #03. Strike a balance between abstraction and volume. Details can never be captured in 30 seconds. #04. A LOT of correct practice makes perfect. Step back from what you've done, compare it to the source, and if you've made a mistake, do not reinforce that mistake by doing a bunch of similar drawings. You will end up having to break those bad habits before you can progress again. The "force" series is a fantastic reference to drawing the figure quickly.