With nurseries and childcare generally, word of mouth is the best way to get a recommendation. If you don't personally know anyone who has children at a nursery there, you could try Mumsnet.
Otherwise, to narrow your search you could start with the top five rated places according to Ofsted - you can see details here. Ofsted isn't perfect but it does check for important things like ratio of staff to children, if the school follows government guidleines etc. You could also look for a sure start centre - generally, any government-backed nurseries will have good standards. You could also ask your health visitor, who probably has a list of good local places.
Once you have got a short list, you should contact a couple of nurseries and ask to come and look round and meet the staff. Then you can find out more specific points - there is a useful list of questions here - but the main thing to look for is the atmosphere. If it seems to be a happy place your child will probably be happy there.