My first 2 were 13.5 months apart. The one thing I would recommend is to get your daughter used to playing by herself for a short amount of time - in her room, a playpen or her cot. This was invaluable to me. Do it before bubs comes along so she's not associating it with bubs. Use it when you need to cook dinner or when you just need some time to yourself. I found DD1 could easily spend 15 minutes on her own playing with toys in her cot. Give her some special toys just for this, so she'll have fun.

Also, make sure she has a doll and show her how to put the doll to sleep, how to wrap it and give it a bottle. Maybe buy her a little chair for her to sit in to feed her doll while you breastfeed. We did this for DD2. She was 21 months and a real mummy's girl when I had my little boy. So before each breastfeed I'd let her know I was about to feed and I'd get her chair out and she could feed with me.

Make sure you warn rellies when they visit to give her lots of attention before looking at the baby.