Maybe start to think about your introduction book to them. Think about what photos you want in it (you, home, bedrooms, car, pets etc etc) and what you want to say to them. The ones you can record your own voice in are definitely the best. How you want to decorate it to make it visually appealing. It took a while to get ours the way we wanted and and we were very conscious that this would be our LOs first experience of us and it needed to be just right. The foster carers used this book for about a month with the kids before they met us. They've been home approaching 3 years and still love to get the book out and look at it. They've memorised the recorded bits and speak along with our voices.
Think about transition cuddly toys. We got one for each of our kids that fitted their personality but also the type of home and lifestyle they were coming to with us. We put them in most of the photos in the introduction book, so on their beds, eating breakfast, in the garden). We slept with them in our bed for as long as we could and then gave them to the kids the day we met them for the first time.
Having bedrooms near ready, it means you can photograph them and put them in the introduction book. Also, once introductions start you'll be too tired to worry about it.
I would caution against having too many 'things' for them. Our LOs would have been totally overwhelmed. They came with quite a lot and much of it was broken and little of it was practical or our taste but we lived with it and changed slowly a bit at a time. They needed the reassurance of familiar things around them.
Adoption UK have a great list of questions that are useful to ask the foster carers, it covered loads of things we wouldn't have even thought of. Might be handy to have an early look at that.
In terms of the matching panel itself be really confident in your answer when they ask you "why these children?"
It's a bit of a leap of faith getting everything ready when you're not officially matched but our SW told us we wouldn't be going to panel if they weren't pretty sure of the match.
It's such a scary, wonderful, exciting, overwhelming time for everyone and it's very very worth it. All the best for the panel.