Any and all pages you create should first be passed by the admin team for approval to avoid losing your work if it's declared to not agree with the preexisting canon. Please be sure to read over similar articles before making any significant changes to the wiki.
The wiki does not have any overly specialized best practices in regard to formatting, other than to use the correct infoboxes for each article. When creating a new page, visit similar pages for formatting help.
It is very important to correctly categorize every page in order for them all to be easily found and navigated. The best way to find which categories to apply is by looking at pages on similar subjects. For example, if you write an article about a planet, you should look at a similar planet type to see what categories it is sorted in.