First, think of a keyword to use. It needs to be between five and nine letters long, with each letter occurring only once. Pick something that people might not easily guess - but which you can easily remember. The example below uses the word 'pyramid'.

Write out the alphabet in one long line. Then write your keyword under the first few letters, with the letters lining up. Then add the rest of the alphabet - remembering to leave out any letters that you've already written in your keyword. Like this:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
P Y R A M I D B C E F G H J K L N O Q S T U V W X Z