Something I’ve never come across before for some reason is Captain Beefheart’s “10 Commandments for Guitarists”. I found this at the ever-informative Music Thing, though it appears on a few sites around the web. The annotations in italics are mine.

LISTEN TO THE BIRDS

That’s where all the music comes from. Birds know everything about how it should sound and where that sound should come from. And watch hummingbirds. They fly really fast, but a lot of times they aren’t going anywhere.
Which reminds me that I once wrote a piece of music on the old CX5m that was based on dozens of transcribed birdsongs – what the hell happened to that?

YOUR GUITAR IS NOT REALLY A GUITAR

Your guitar is a divining rod. Use it to find spirits in the other world and bring them over. A guitar is also a fishing rod. If you’re good, you’ll land a big one.

PRACTICE IN FRONT OF A BUSH

Wait until the moon is out, then go outside, eat a multi-grained bread and play your guitar to a bush. If the bush doesn’t shake, eat another piece of bread.
Strangely enough, I have done this, apart from the bit about the bread. Next time…

WALK WITH THE DEVIL

Old delta blues players referred to amplifiers as the “devil box.” And they were right. You have to be an equal opportunity employer in terms of who you’re bringing over from the other side. Electricity attracts demons and devils. Other instruments attract other spirits. An acoustic guitar attracts Casper. A mandolin attracts Wendy. But an electric guitar attracts Beelzebub.
So what does a yobstick attract? Nearly Headless Nick?

IF YOU’RE GUILTY OF THINKING, YOU’RE OUT

If your brain is part of the process, you’re missing it. You should play like a drowning man, struggling to reach shore. If you can trap that feeling, then you have something that is fur bearing.

NEVER POINT YOUR GUITAR AT ANYONE

Your instrument has more power than lightning. Just hit a big chord, then run outside to hear it. But make sure you are not standing in an open field.

ALWAYS CARRY YOUR CHURCH KEY

You must carry your key and use it when called upon. That’s your part of the bargain. Like One String Sam. He was a Detroit street musician in the fifties who played a homemade instrument. His song “I Need A Hundred Dollars” is warm pie. Another church key holder is Hubert Sumlin, Howlin’ Wolf’s guitar player. He just stands there like the Statue of Liberty making you want to look up her dress to see how he’s doing it.
I never leave home without mine.

DON’T WIPE THE SWEAT OFF YOUR INSTRUMENT

You need that stink on there. Then you have to get that stink onto your music.

KEEP YOUR GUITAR IN A DARK PLACE

When you’re not playing your guitar, cover it and keep it in a dark place. If you don’t play your guitar for more than a day, be sure to put a saucer of water in with it.
Mine does live in a cool, dark place, but usually gets left a half-cup of cold, black coffee – maybe water would be a better bet.

YOU GOTTA HAVE A HOOD FOR YOUR ENGINE

Wear a hat when you play and keep that hat on. A hat is a pressure cooker. If you have a roof on your house the hot air can’t escape. Even a lima bean has to have a wet paper towel around it to make it grow.
Well now, I used to have a hat – the “Silly-bugger-time hat” as it was known (actually a tweed deerstalker). I refuse to wear a baseball cap as a matter of principle, but may need to invest in something with a modicum of style to meet this rule.