The author's website has tons of before/afters!

https://www.drawright.com/before-after

Incredible results for only six days.

I was positive I could not draw objects from life. But some of the tricks in that book showed that even I really could (in the right frame of mind) trace/render/copy/draw from life. Now I just needed practice.

Get this book, go through it, then look into drawabox if you are looking to draw from life.

For constructivist illustrations or styles like manga, I'm still learning.