First of all it is necessary to define your language or the tags that
will be allowed in your XML. This information is stored in a DTD
(Document Type Definition). You can create your own or choose an
existing DTD. There exist already plenty of them from music to
technical documentation.
If data as to be stored in your format by a lot of people it is a good
idea to write an interface.
Finally you need your data to be rendered. That implies the creation
of a stylesheet, that will define the transformation of your data into
a common display format like HTML or PDF. You can also decide to
export the data to another system like a database.
