To answer that would take a book.
Try to narrow things down.
Have you started teaching them already? If so, what have you tried, and what problems are you encountering?
If you haven't started:
How many will be in the group?
How long will the lessons be, and how often?
Is this intended as a serious class or something like a play-group?
What facilities will you have?
Have you any previous experience of teaching? of teaching English? of teaching children?