He writes me an email:
We somehow ended up talking about things we absolutely judge by first impression. We both read a lot and widely in general, and it was a fun topic.
An easy one for me to note was that I skip technical/professional/academic work that is far enough outside of my expertise that I know the baseline knowledge assumptions are beyond me. Imperfect, but in general, a good filter.
I skip nearly all books by politicians, executives, and similar people. Even when people tell me that one is good, it usually isn't.
I really dislike reading music reviews. They almost never seem insightful, and rarely tell me anything I didn't realize I wanted to know.
Sort of the opposite of the above filters, I tend to really enjoy reading applied trade books for things far outside my expertise. An example is that about six months ago, I read a treatise on elevator traffic management that was fascinating.
What other principles can you think of? I go to Mary Riley Styles Falls Church Public Library and check the non-fiction Return carts, to see what other people have been reading.