Reflect reflect reflect!!! But don't go overboard like me and reflect upon reflecting ad infinitum, include content too
and also if you like colourful stuff, make it colourful! Photos, lyrics, quotes, drawings, whatever is relevant to your work or inspires you belongs in there and if you genuinely enjoy adding to it, you'll keep coming back to it and not seeing it so much as a task. It becomes treasured by the end of the year. I still miss mine, my teacher has it at the moment as far as i know
Seconding the recommendation to annotate, you will definitely rack up a huge amount of sources over the course of the year, just makes it easier when writing your reflection statement. It's really easy to start neglecting this but just make sure that you've written enough on each significant source to footnote it, even if you're not doing a full-blown bibliography.
I actually had separate journals, one was an expanding file for printed copies of my major work that I'd edit and reprint about twice a month, and twice a week as the date neared. Another was a display folder for material our teachers gave us - you know the kind, huge stacks of stapled paper detailing course requirements, timelines, assessment information, and sometimes sample works. The third, and main, was a green A4 200 page notebook, which was massive by the end of it. Before handing it in, I bought a big red binder folder thingie, filled it with plastic sleeves, ripped apart the notebook (that was painful) and stuck everything in chronological order so the drafts were integrated. Saved me from using a lot of glue for each draft, and looked pretty cool too.