R.J.
Make sure she's a part of everything.
Use the words "your sister" instead of "the baby" or "my baby" or "our baby" as much as possible. If she's there for the birth... she's quite old enough to be sat in a chair and hold her sister (I held my sibs starting when I was 2, sitting on my mum's lap.. and could hold them on my own when I was 5). My parents made a big deal of "trusting" me (with a smile, instead of as a warning), as they outlined how to do stuff. They also always said Yes, or Yes IF, or there you go, JUST like that, or Close... make your hand a little softer, PERFECT. Made a big difference from watching my friends who heard no no no no no no no, not like that, you're doing it wrong, etc. New babies in our house also meant the unparalleled treat of a tv being moved into our room with cartoons playing quietly all night long for the first 2 weeks. So if the baby woke us up, we could fall back to sleep with the pink panther or transformers or my little pony (dates me, doesn't it?). We were also always welcome. It wasn't "go back to bed"... it was "want to come say good night to your sister/brother?" or "want to come sit with us while I nurse and chat?". We'd invariable get tired minutes later and go back to bed. But all I remember is how warm and welcome we were to be a Part Of. And then we got bored with the shiny new thing... and had fun (in the day time elsewhere, or went back to bed and fell asleep warm and comforted.
Moving can also be reeeeally fun with kids. There are boxes to play in, floors to slide around on, cartwheels indoors to be had. There are 1000 games you never really get to play UNLESS you're moving. Plus there's "door holding", coloring, movies... drawing your height on a door for the first time. We moved every 2 years growing up and it was the MOST fun... because it was a great big giant game. ((When else can you do silverware catepults, ride your bike in the house, or slide on a box down the stairs and halfway across the living room? Indoor sleds rock!!!)) If you'll be repainting... there's also the GREAT joy of being told to draw on the walls to your heart's content. (Only got to do that twice. SO much fun)
It takes longer to make things fun for kids... but the great memories, and not having the stress of fights and hurt feelings... IMHO makes it all worth it. My H despises how long I take to do things since kiddo was born. But when he's with ME he's laughing, or running "races" to clean, or going on scavenger hunts. With my H, they're yelling at each other and there's tears. The extra time is worth it.
