Prepare the student's room with fresh sheets and towels and make sure the room is properly aired. If it is hot, provide a fan. If it is cold make sure there is enough bedding and supply a heater if necessary. Purchase enough food for the first day or so making sure you have items for a lunch box if requested in the booking.
Be available (or if you have to be at work at that time, arrange for a grown up) to open the front door upon the student's first arrival.
In addition you can choose to familiarise yourself with the customs and culture of the country where the student is coming from so you can understand your student a little better from the beginning of their stay with you.