Here’s one of my favorite practice tips. Basically the tip is that you get ten match sticks (I use pennies) and work on a section of music you’re having difficulty with. When you play it perfectly you slide a matchstick over to start a new pile. Play it perfectly a second time and you move another match stick. Repeat until you have ten match sticks in the pile. If you mess up you start over. It can be really hard but it really works, too.
Here’s the link to the original tip. http://www.acousticguitarforum.com/forums/showthread.php?t=7560
I’m skeptical as to the truth of this story, mostly because I don’t think match sticks were commonly available “way back then”, but either way it’s still a great tip!