The instructional manual is an excellent application in the field of technical writing. A good instruction manual will tell the user everything he needs to know to be able to carry out a given task correctly, efficiently and safely.
Identify the people for whom the task is intended, and write to their level of comprehension. Knowing your audience is a crucial part of good technical writing.
Write a table of contents at the front of the manual if your manual will be more than a few pages. If your manual will be very long, include an index at the back.
Write a brief introduction that describes the task in qualitative terms. Give the user a sense of what the task is and what the final result will be. Take this opportunity to provide any important general advice that will help the user to perform the task correctly and efficiently.
Provide, as necessary, a list of the relevant equipment and items the user will need to complete the task. If your instruction manual is for product assembly and is accompanying the product to be assembled, include a separate list of all the parts that should have been supplied to the user.
Clearly label any significant risks that may lead to death, injury, property damage and other hazards. Use language that conforms to the legal codes in the jurisdiction where your manual will be sold.
Write out each individual action in the instructional process as its own, distinct step, providing any specific information that the user will need to complete that step. These individual steps should be unambiguous, literal and straight to the point.
Illustrate the manual with diagrams and figures whenever doing so will help clarify a difficult step for the user, provided that there is room in your manual for you to include the graphics.
Include, at your discretion, an itemized list of advice to help guide the user in completing the task.