Journals are not at all required, but it's a great way to keep things organized. If you choose to create a journal, there is no specific way to organize everything but you should provide the following things:

Your Character: As well as his/her level, guild, gender. You can include as much information as you want about your character; a biography, description, etc.

Battle Statistics: Win/Loss Ratio and Recorded Battles

Skill Book & Items For easy reference when battling. Make sure to update your items frequently.

Journals must also be character-specific. Meaning one character per journal, or at least one character per page. Make sure to title them with [Username] - Character Name. Also, please don't post in journals other than your own without permission.