Write your first draft.
Check your information is complete and accurate. Are all the phone numbers correct? Is all the information up to date? Do the links work?
Read over your writing with our style points in mind.
Imagine what an outsider would make of your text. If possible get a second opinion. It’s very difficult to proof your own work as you already know what you are trying to say. Get someone to peer-review your work.
If you are writing for anyone who is not familiar with your topic, use feedback from someone from your target audience. Rewrite anything that confuses. Add any information that’s missing.
At the very least set it aside to read with fresh eyes later.