What do you mean teenage notebook?
I don't know if this is what you're asking for but I would say that putting together a collage of really cool pictures is always nice, and so are quotes, or ripping out parts of magazines that you like and pasting it all together.
Pictures of you, friends/family/memories are always nice too, randomly paste them and write what the memory is about and I taped a leaf into my journal once, it was a memory of the first date my ex boyfriend took me on