Right, I don't want this guideline to be too constricting, so I'll be very brief with this:
Include your IGN. That is something you have to do.
Other than that, there are no requirements
However, if you want ANY chance, I suggest you include a lot of information. Personal information, maybe something about your morality, and of course the good ol' details on what you'll do.
For an example of what is, in my opinion, the best application ever, click here
Steam (and Skype): Zairuen