If you are writing for a web site, your writing must be shorter, in shorter sentences, and broken into segments that can be easily linked together. Agree on your key messages. You will save time, if you and your key players agree on what you want to say in advance. You'll save headache and heartache if you outline these ideas in advance. Use active voice.
Writers fill the technology world with passive and therefore boring writing.
Make your reader part of the action by using active verbs whenever possible. Hire a proofreader. After you have spent several hours or days with your writing, you will stop seeing little mistakes. Hiring a proofreader, or asking someone else in your office, is a sure way to keep your copy clean. When in doubt, get help.