Hi there,
I have just the thing for you - check the video demo out here of me teaching a six year old, and also an eleven year old (separately).
How to teach a child to speak English
That video will give you the idea of how to go about things.
There are free games you can receive by email to use one on one.
Then there are also plays and skits that are ideal for that age - there's a free on one my plays page that you are welcome to.
You've got to keep your approach light and fun and correct pronunciation v. carefully and not obsessively as at this stage you REALLY don't want to put them off!!
All the best