Include all the materials needed to play your game.
Especially for the self-made materials, include all the materials users will need to create your game.
If you discover you need more materials while you are writing the instructions, you can always add them later.
Each step should involve only 1 action, such as, "Cut all the pattern pieces."
Begin each step with an action verb (i.e. measure, draw, glue, etc.).
Use coloured and/or bold font to accent important information.
Use bullets if you want include substeps.
Include tips, warnings, and pointers along the way, as necessary. When you write a tutorial, it helps to tell readers what mistakes you made that they can avoid, as well as useful shortcuts you learned through experience.
Provide a picture for each step, if possible. (source WikiHow)
Be sure to run the spelling and grammar check, as well as to read your tutorial out loud several times through in order to identify and correct any mistakes.
You may also want to have someone else read it and provide feedback so that you know your tutorial makes sense logically and chronologically, and that your instructions are easy for readers to understand. (source WikiHow)