I can tell you how we book our weddings but it's different for every photographer. For example, you post your entire price list on your website but we only include a starting price. Some photographers don't post a price at all. We generally take a very hands off/low pressure approach just because that's our style.
When we get an inquiry, they're typically asking for the entire price list. We first see if we're available on that date, and if we are, we email the price list and basically ask them to meet up to get to know each other and look at more photos. Some email us back at that point and some do not. Some people ask a lot of questions over email before agreeing to a consultation and some just agree to meet up right away.
We then have a consult and basically try to get to know the couple, talk about how they met, where they're from, their family, whatever they're willing to talk about. Then we show some pictures, some albums and then let them ask us any questions. After that we basically tell them that in order to reserve the date we need a retainer and signed contract.
Once we get home, we send them a contract and tell them that once they're ready to book they can send us the signed contract and retainer. At that point, most people send it in but some do not. We book about 80% of the people we meet up with... but probably only 30-50% of inquiries turn into consults (less if we're pretty booked up already).