Here's a much easier way to make your bookshelves look put together without all the fuss: group them by color! it's actually that easy - and it makes such a difference, especially if it's in a den or a commonly-used room in your home. Check out this one below (from my sis's house):
These Ikea bookshelves (available in white, too!) retail for about $80 and are perfect for bins of toys and books! The grouped books are ever so pleasant on the eyes. And the combination of stacking the books alongside the standing ones give the shelves much more dimension and personality. Love it!