Miss B was 25mthss old when Miss Em was born, she was already in a big girl bed, we involved her in absolutely everything, from decorating baby's room, to taking her to the appointments. We always talked about the baby to her and how she would have to share her stuff etc... but we did tell her the only item she did not have to share was her "Pinky" her bed cuddle toy.
When i went into labour we told her that the baby would be here soon, she was very protective off me when i was at home labouring which was so sweet! and when Miss Emily arrived, Miss B was the first one (apart from DH) to see her, we wouldn't let anyone else visit until she had meet her sister and we spent time as a family! she came up to visit every day i was in hospital. and when we got home we involved Miss B in everything again, from the baths to the nappy changes to picking out her sisters clothes. When Miss Em would cry too we would ask Miss B what do you think is wrong with her and how can we stop her crying, which made her feel important!
We never said stuff like "baby this or baby that", and we never left Miss B out.
so we didn't have any problems of jealousy or anything like that at all, and still haven't to this day it was a very enjoyable time for us all

Oh and Miss B brought Emily a gift and Emily brought Miss B a gift