I was on yearbook in high school too, and everyone has been right so far. Color will make a big difference, even if it's not the whole book. At my school, our People section and of course, the seniors were in color. Everything else, except for people who bought color ads, was in black and white.
Also, we were taught to take our pictures slightly off center. This was just in case that picture became your main picture that ran across the entire 2 page spread. The center of the photo will be in the gutter of the book. If the object of your pic is in the center, then it/she/he/they won't be seen or severely deformed
, so we always took ours a little to the right or left.
Like 2 tuff said, stick to the deadlines. Some of us on the staff gave up a day of winter break to get our color pages in on time.