We use black paper for the background. I select books around specific themes and then have the students guess what the theme is. I have used survival, award winners, time travel, banned books, etc. You can use everyday and famous slogans and tweak them just a little to create an attention getting bulletin board. You could have pictures of friends reading, book jackets, or pictures of book covers.
Kids love to see themselves on a bulletin board.
Since my school was new, I had many many book jackets and wanted to display them. I kept the book jackets as a frame and changed the middle of the board for an entire year. Here I have a book quote from Groucho Marx. For fall I had a tree with falling colorful leaves. Christmas was a big gold star.