I always thought that I was good at grading but I'm still learning like most of us here. One of our members, Jason Poe (physics-fan3.14) put together a great tool for those that wish to learn more about the art. It has been a great help to me. There is so much to understand. It's called The Art and Science of Grading Coins. I'm reading it for the second time trying to soak it all into my old brain. It's a great read.
Also Don't forget Holiday30 at amazon for 30% off one book up to a $10 discount until Dec 1st. Handy for anyone looking for a book this season!
This book is no longer on my wish list. It's in transit, soon to be on my bookshelf. Good winter coffee and fireplace reading.