Authoring a document for the LDP is a several steps process.

Have an idea

It's much easier thant most people think. If you find a man page difficult to understand, an already written HOWTO obsolete or you find yourself writing hints on configuring your favorite mail agent, you are ready to go to the second step :-)

Have the knowledge

There are two situations dealing with usefull results.

You are already an expert in some part of the Linux World, and you want to share your expertise. This may simply mean you are a student and made a white paper or a thesis about the subject and nobody else did wonder to write on the subject for some years.

Or your are a complete newbie (newcommer) on this aspect of Linux (for example setup a Kerberos server on a new computer), and you don't think the already available documentation is really friendly. As long as the document is clearly quoted, your experience is very interesting. Experts have often forgotten what they did initially. Writing down the beginners problem may be invaluable for the other beginners. Write a "Kerberos for beginners HOWTO" (just an example).

Write the document

Write a well organised document is a challenge. It's very difficult. Most of the time it mean writing it in he's mind and dream on it. When you can't sleep because the document runs in your head, get up and write it down on a paper.

Write it on a paper first, or on your favourite word processor. Chance is you will have to rewrite it often before being glad about the result.