Keeping a diary can be very interesting. Here's how to start one up :)
You don't need much to keep a diary. Any old notebook would do as long as it has lots of pages or you have lots of paper (that fits :P) I recommend an 100 page diary (if it's a notebook) But if you can add extra pages, it doesn't matter. All you need now is a pen/pencil. I like to have a special diary set with my fave writing pen and pencil. Don't forget it's not just about writing, but you can draw or put in picture or whatever. That's why I have a mini stationery set for my diary.
When's the best time to write? At night so you can write about you day (if it wasn't scary � otherwise nightmares!) or in the morning aobut your dreams. Don't forget to include things such as: Going away, holidays, site, boys, school, friends, homework, worries/problems etc. This is your personal space!
What else? It would be interesting to leave a number/address at the front of your diary, in case it gets lost. Or if you're moving, you could leave it behind with your new address :) Include drawings and little objects from the day.