You should ensure that your child is as independent as possible- physically, emotionally and socially. If they can look after themselves in these areas they will feel secure and confident and readily settle in.

It would help greatly if they are able to-

Button and unbutton their coat and hang it up.
Use the toilet without help.
Use their hanky or tissues when necessary.
Share toys and playthings with others and “take turns”.
Tidy up and put away playthings.
Remain contentedly for a few hours in the home of a relation, friend or neighbour. If they have had this experience, then separation from parents should not be upsetting.