In fiction, I read to be entertained. That being said, I will tell you first what I do not like.
1) Books written in the first person. This will immediately turn me off and I will return the book to the shelf. To me, there is nothing more boring than wading through 400 pages of "I".
2) Books whose protagonists are unbelievably perfect and who are capable of performing acts that can only be performed by about 1% of the population. Think James Bond. A protagonist with whom I can identify will be a cut above Everyman, but he will also possess some flaws and will not be able to ride the world roughshod at his will.
3) Fantasy, forget it. I enjoy Sci-fi if it is at all within the realm of possibility, but a man morphing into a wolf in mid-jump is too much of a stretch for me.
4) I am not being chauvinistic here, but I have a hard time reading books written by women. When I read a book I really enjoy, I become part of it. Men and women are very different in their thinking and their approach to various situations. Call it a flaw in my character if you want, but I cannot identify with a female protagonist, and I have found almost no female authors who can "get inside the head" of a male one.
Reading the blurbs and skimming a few random pages of a book tests these criteria quickly.
When you read this, please remember that I am 67 years old, have been reading for a very long time, and have grown very ornery and particular in my later years.
How do you decide on what fiction you want to read? Comments?