Suggested supplies to choose from:

• 1 blank art journal or printed book
• Paints: watercolors, acrylics, Jacquard brand translucent colors, artists' inks.
• Applicators: brushes, sponges, toothpicks.
• Pens: Pilot V Ball or other roller ball pen, paint pens, squeeze paints, archival markers, photo tinting markers, colored pencils.
• Papers and fabrics: card stock, tags, bingo cards, vellum, ticket stubs, newsprint, magazine clippings, stamps, fabric scraps, colored threads, ribbons.
• Scissors, hole punch, craft knife, cutting mat.
• Adhesives: UHU or Avery brand glue stick, white craft glue, mono-adhesive double-sided tape.
• Photos: instant camera photos, laser color or black-and-white copies, postcards, drawings.
• Embellishments: lace, hankies, charms, beads, alphabet beads, minibottles, screen, grommets, tassels, wire, dried flowers.

Directions: Because many pages are thin and your work may be heavy, you may want to adhere two pages before working on them. Next, I prefer to create the backgrounds for several page spreads in advance. Begin by dripping or brushing on color and let dry. Taking one page spread at a time, come up with a theme. Don't glue anything until you have rotated the items you are using to find a look you like. Create one focal point in the design to avoid its being too busy. If you are not into collage art, paint or draw pictures.

Tips: If using a blank book, you may need to remove some of the pages from the back of the book to ensure that the cover will close. To hold small items, glue an envelope to a page in the back. Feel free to let your designs extend beyond the pages by attaching foldout panels or sliding cards. Tear edges off the pages for a textured effect. Use your craft knife to cut out shapes, frames and pockets. If you have trouble getting started, begin by making lists in your book that you can add layers to. The ideal book is one with a good balance of color, design and balance. Don't be afraid to try a new technique or color scheme. Start with a theme that will come easy for you: Spiritual, self-expression, travel, family history, gardening, pop culture, music, movies, etc. Look at thrift stores or used book sales for unwanted but eye appealing cookbooks, kids books, textbooks, old dictionaries. Choose ones that are made from heavy paper and will work well with a variety of mediums. Don't feel you have to decorate every single page, choose random pages that comes with interesting photos or words that you can build a theme around.

And if that's not enough, see her stuff for inspiration at
http://www.craftychica.homestead.com/
Enjoy!

I suppose you should agree on a general theme before you start. And let everyone know in advance, so they can start accumulating things they might want to use.

Are there any other things I should think of in advance?

(Thanks for the links taunial -- it's a great start!)