If your group has a "foster guide", most of your questions will be answered. If not, find out whether fosters are allowed to sleep outside their crates (especially at night.) Find out whether fosters are allowed on furniture. Make sure that everyone is muzzled outside. Be cautious at mealtime - food aggression is fairly common. I'm sure that others will chime in with what I've forgotten. And have fun - love them and spoil them just a little, but remember that you are taking care of someone else's dog - it helps you to let go if you think of them as someone else's dog right from the start.

If you work with groups that get dogs right off the track, you might want to consider fostering broke leg or injured dogs. I live about 2 hours from the group that I work with and since it's a long drive for me to get to meet and greets or just to switch dogs that might be going on pet runs, I do the long term fosters. They stay with me a month or two, just long enough for them to heal up, and then off they go up the eastern seaboard to their forever homes.