If your toddler is having trouble going to sleep, develop a soothing, consistent nighttime ritual.
Familiarity breeds contentment for toddlers.
When you're expecting a second baby, buy your child their very own baby doll. Play-feed her, dress her and take her on outings. It's a great way for your first child to get used to the idea of taking care of another person. If your child doesn't like taking a bath, make it into an expedition. Have her put on some goggles, and throw floaty fishes and other animals into the bath with her.