Somewhat by accident I wound up a fluent reader before going to school, and read voraciously from then on. I'm not sure how many books I've read, but probably no more than 20,000 (I have some friends -- and have knowledge of some -- who have read quite a bit more).
Fluency really helps because there are fewer really worthwhile books than other kinds (this is similar to "most ideas are mediocre down to bad", in no small part because good ideas are a rarer set of insights, and they have to be formed in our not wonderful commonsense environment).
In third grade I started to put a lot more effort into really remembering what I read (it finally occurred to me that I'd have to reread most of the books if I didn't).
Because of efficiency, etc., I generally finish virtually all books. I often read several books at a time. I don't spend all day reading now, though I certainly often did when I was younger.
Reading often leads to other reading. I also read reviews of books. A really fun find ca 1970 was The Whole Earth Catalog, which listed thousands of "tools" including hundreds of books with small very useful reviews. Most of these were very worthwhile (and all the books in the WEC were the first books in the PARC library).
I sympathize with the writer below who wished for a little description for each book on my reading list (annotated bibliographies are very helpful).
I follow my nose (and try to use other dim senses when possible).