I have usually worked on creating User Manuals for my company and so I will write up some posts for writing technically while creating User Manuals.
- Provide a real (physical) User Manual with the product: don't make people read a pdf.
- Make sure the instructions actually map on to the product in all respects.
- Include a one-page quick start guide.
- Present instructions as step-by-step procedures.
- Tell the user what functions there are, and what they are for — not just how to use them...
- ...but avoid marketing waffle (they already bought the product!)
- Ensure that the writers are part of the product design team.
- Write the user manual in sync with the product's development timeline — not under pressure of shipping deadlines.
- Make sure the writers have the product, understand the product, and actually use the product as they write.
- Consider the needs of disabled users (i.e., low vision, colour-blind) and provide alternative manuals in Braille, large print, audio etc.
- User-test the product and the user manual with real users (including disabled users).