Teaching her to be independent. Getting dressed, putting on shoes, remembering her things.
Loads of opportunities in the summer with going on day trips, swimming, playing in the garden, going on trampolines etc etc to practice clothes, shoes and the art of remembering to pick up your own cardigan and bag.
Picnics and cheap meals out, being left at a friends with out mum for an hour or two.
Practice with unfamiliar food and different people. My Mum is a brilliant cook, I hated other peoples food for years.
Basically anything that encourages confidence that she can be independent.
Clearly depends totally on how much time she's spent at nursery or preschool, but keeping it up through the holidays helps.
Clearly any reading to her and learning numbers etc is good, but there is plenty of time for that.
Our reception children have year six buddies and certainly this works best if the new intake have the confidence to talk to the older children and join in.