I'm sorta surprised people need a mnemonic for cardinal points. 
We were given a ton of them for navigation and (nautical) rules of the road. My favorite:
"Green to green, red to red, all is well, go ahead. (When in danger, or in doubt, run in circles, scream and shout!)"
Some others:
"Red over green, sailing machine"
"Red over white, fishing at night"
"White over red, pilot ahead"
"Red over red, the captain is dead" (Vessel not under command (adrift))
We were given a ton of them for navigation and (nautical) rules of the road. My favorite:
"Green to green, red to red, all is well, go ahead. (When in danger, or in doubt, run in circles, scream and shout!)"
Some others:
"Red over green, sailing machine"
"Red over white, fishing at night"
"White over red, pilot ahead"
"Red over red, the captain is dead" (Vessel not under command (adrift))