It may be more accurate to say the rules for recording recipes, which is a different thing than creating/writing recipes.
1: Use a descriptive title
Don't name your recipe Chicken and Noodles. Think about the herbs and spices you used. If it's lemon and rosemary, call the dish Lemon Rosemary Chicken with Broad Noodles.
2: List the ingredients in order of use
Ingredient lists allow the cook to assemble everything s/he needs before starting the cooking process. Include how much of the ingredient is required, and how the ingredient is used, ie. 1 onion, chopped
3: Pay attention to how you write the amounts
Writing "1 onion, chopped" means you chop one whole onion. "1 cup chopped onion" means chop enough onion to make one cup. The first direction is ambiguous; the second direction is clear.
4: Write the directions in the right order
The first ingredient on your list should be the first ingredient you deal with in your directions. Be precise. Don't write, "Cook the meat a little bit before putting it in the slow cooker." Write, "Brown the meat in a fry pan, drain, then add to the slow cooker."
5: Include essential information
Just after your descriptive title, and before your list of ingredients, tell the cook how many portions this recipe makes, required oven/appliance settings, and any substitutions that may be used.