I'm guessing by directions on a map you mean North, South, East and West. There are several easy ways to remember them and the directions they point in. My personal favourite which I learned as a child and still use today is:
Never
Eat
Shredded
Wheat
This is the one that has always stayed with me, but here are some more you might find easier to remember:
Never Enjoys Stinging Wasps
Naughty Elephants Squirt Water
Never Eat Soggy Waffles
This way to remember something is known as a mnemonic. The beauty of this memory aid is that you can use absolutely anything, and infact, if you make it up yourself you are probably more likely to remember it.
Other famous mnemonics
Every Good Boy Deserves Football (musical notes)
Richard Of York Gave Battle In Vain (colours of the rainbow)
My Very Elegant Mother Just Served Us Nectarines (solar system planets)