I posted this back in March for someone else:
A couple of suggestions we got that we tried and found helpful:
1. Talk about the baby, and allow the older child to say "I love you" and/or kiss your belly before the baby's born. It seemed natural to us until we realized some people didn't even TALK about the baby until s/he was born!
2. When the older child comes to visit you at the hospital, DEFINITELY have a gift for her from the baby. We got my son a little dump truck from the baby, and he told EVERYONE that "fani" (stefanie) got it for him. Something small that you know she'll like.
3. When she comes to visit you, try to not be holding the baby when you welcome her in the room. this way you can hold the older child and introduce her to the baby.
4. Encourage friends and family to greet the older child first (instead of the baby) when they come to visit you at home.
5. Try to keep the older child's schedule as regular as possible (especially naps!) during those first weeks.
6. Having another doll that the older child can "take care of" whiel you are taking care of the baby is fun too! My son changes a baby doll while I change the baby, etc.
7. Get a few books about bringing a new baby home. My son enjoyed reading them for a few months after the baby was born -- he recognized things that were going on, and he could "tell" me that yes, the baby cries, or "yes" they have stinky diapers.
8. Help the BABY sleep AS MUCH AS POSSIBLE. You are probably a pro at reading sleep cues now that your'e on number two. The less crying that the baby does, the better the older one will adjust/not feel jealous or frustrated. The *first* sign of fussiness tend to the baby's needs -- even if company is over. A happy baby makes for a happy household.
Enjoy! Two is a blessing!
T.
ps - I guess that's more than "a couple"! I hope it's helpful though!