Danbooru uses DText for all formatting.
To create an internal wiki link, wrap the title in two sets of square brackets.
By default when you search for a keyword Danbooru will search both the title and the body. If you want to only search the title, prefix your query with title. For example: "title:tag group".
The Danbooru wiki has no specific style guide, but here's some general advice for creating wiki pages for tags:
Use h4 for all headers, h6 for subheaders.
Bundle any relevant links at the end under a See also section.
For artists, include the artist's home page under the See also section