What are some tips when organizing and decorating a shelf?

We just bought this huge see-through shelf from ikea (a href="http://www.ikea.com/us/en/catalog/products/60071358)." rel="nofollow"http://www.ikea.com/us/en/catalog/produc…/a We have a lot of books we can put on it, but we also want it to look decorative with candles since it's one of the biggest pieces of furniture in the room, etc. How do I organize the shelf so it doesn't look cluttered, or the books overwhelming? Thank you!