My particular fave point:
5. Quiet Loners
Whenever they find some whackaloon with a collection of severed heads in his freezer, they always trot out the neighbors and you get that classic line: “He was always so quiet.” And the assumption becomes, oh, that seemingly nice-and-quiet chap next door needed his quiet time because he was too busy with his hobby of decapitating dudes. On the other hand: hey, maybe him being quiet and alone all the time made him crazy. Maybe you spend too long cooped up with yourself the carpet starts moving and the wallpaper shifts and the room starts to whisper, You know what would be awesome? A sweet-ass collection of severed heads. Get on that. This is probably a good time to remind you that writers happen to spend a lot of time alone and cooped up with themselves. Just, uhh, putting that out there. What, this old thing? Just a hacksaw.
I’d add another:
What? Doesn’t everyone ask people at cocktail parties what it would take to get them to drive a car off a suspension bridge or break into someone’s house for the sole purpose of raiding their refrigerator and eating meat naked in the kitchen sink? (true story–that actually happened, but I’m sure a writer somewhere had already put it to paper before that) Writers should go out in public at least three times a week to interact with people who are not writers. Not only does that teach us how to behave like normal people for a few minutes (one hopes), but it can give you lots of good ideas for secondary characters.
Happy reading, happy writing. And put that hacksaw away, where nobody can see it.