Re: Any tips on how to get autographs?...
Some pointers.... If you are getting autographs on a baseball, always use a pen. Never a sharpie. They fade and can bleed quickly. If you are going to have a baseball card signed, rub baby powder on the card before hand. It will dull the glossiness off of the card, and the sharpie won't bleed (rubbing and eraser over the card also works). With a hat, I would go with a sharpie. I have a hat signed by Lee Smith in pen from the early 90's on the underneath of the bill, which is fine, but you can't really display it.
As far as who signs/doesn't sign.... I have no clue for you, but figured I would give you my other pointers to help out with the autographs if you do indeed get some.