Color-coding is the easiest way to give each child her own space, and it makes organizing and cleanup easier, too. First, create separate areas with color blocking. Use painter's tape to outline a shape, then fill it in with paint. To outfit the space, provide a mix of storage bins and buckets in each child's designated color. They'll corral toys and give each sibling special places to stow treasured items.
For a pulled-together look, outfit the beds with plain matching covers, then customize each with fun pillows and patterned sheets like those shown here (Dot to Dot Percale Bedding, from $25; garnethill.com). To add a homemade touch, whip up some monogram cushions. Start with a plain pillow cover (ours is a 19-inch square). With fabric glue, adhere a felt circle and letter (our circle measures about 10 inches in diameter, and our letter is 7 inches tall).