Take some time to research those services you intend using for your wedding day - services such as photographers, wedding car hire companies, florists, caterers etc. Check out venues for the ceremony and reception. (Often a venue will cater for both - as well as the evening party)
You may of course intend enlisting the help of a wedding co-ordinator who will do all the research for you. They will have many contacts in the wedding industry.
Convey your requirements clearly to those you wish to use and book the services that give you confidence (not necessarily the best price).
County Bride Wedding Etiquette