It is ideal to have a consistent tone of voice across all copy on a website. This creates continuity and prevents the content and organisation appearing fragmented. If there are a number of people with editorial rights to the site, you may like to have one or two central people to run copy through/sign it off to help maintain the organisation’s voice.
Use consistent formatting when laying out text (i.e. using headings, subheadings, making text bold etc) it is best to have a standardised way of doing this.
Always keep your audience in mind when creating copy for your website. Try to think about what they would want to get from the site and what tone of voice is suitable for them.
Headings (titles) and subheadings (summary) have greater importance than normal paragraph text for search engines. Try to think about what they contain and make the content meaningful and refer to key points of the paragraph text.