I had a great childminder for c7 years. I'd ask;
How much experience do you have and with which age groups?
What training have you done?
Could you tell me about a typical day? - what do you do with the children/babies each day?
How do you adapt activities as babies become toddlers and up to age 5?
Do you charge for outings? if so, is it simply entrance fees or also petrol?
What sort of meals do you provide?
How flexible can you be about any changes to times?
What do you do if one of the children is ill - can you still look after them?
Do you have children of your own? (Useful to find out about them, attitudes to school etc - range of activities own children do)
ALSO - check for yourself what the home feels like - is the telly on during your visit? If so are you OK with that or not? Are there signs of varied activities eg good range of toys, books?
Do you have Health and Safety and First Aid Training and do you mind shoing me your certificates?
Could you tell me the names of a couple of other parents I could speak to for references?
Also check registartion with local authority.
Persoanlly for me it was a combination of all these things, but other mothers' opinions counted for a lot. I was informally warned off a couple of CMs - we are still friends with the lady and family I eventually chose after interviewing seven.