When you write the instructions list all the things that you used in the experiment.It may seem silly,but you should write down everything. you should even write down the pencil and paper that you used to take notes.
next,be very clear about what the steps are. give as much detail as possible. label each step with numbers to show the order of the steps. use words like first, next, then and finally. draw little pictures to show your steps. make sure to show the special features,or details,of any objects. read over what you have written. make sure the instructions make sense. ask a friend to read your instructions. see if they understand what to do. when your instructions are clear, type or write them neatly for your display at the fair