Well for me I start with a questionnaire I share with the couple. It gives them a list of photos to chose from. For example do you want you with each all attendants, you with each attendant, your partner with all attendants, your partner with each attendant, and so on. All of our forms are gender neutral. The form has 72 standard choices. Plus it gives them the ability to list their own photos that they really want and I have not thought off.
From there the website tells them you need X time to give these photos (calculated by size of the wedding and how many pictures they asked for). So they know, 10 weeks before their wedding, they have to accommodate a certain block of time to get everything they want.
I also go see any location I have not shot in the last 2 years. So I don't have to be imagine what can happen on the day of, I already know what's going to work, how the natural light falls etc. For example if they know they want a sunset picture I can tell them sunset is at 6:18 so I need 6:15 to 6:35 to be sure of that picture.
We have a meeting the week before. So me and the second and the assistant know what we need to make sure we get and what we need to focus on. I also meet with the coordinator if they have one so the schedule accommodates the couples photo needs.
And I take a crap load of equipment. 8 lights, various grids, gels, soft boxes. It basically fills the van but I have at my disposal any tool I need.
The day of the assistant has a list of what photos we need to get, that list is mapped into the schedule so it knows we should try to get the bride/groom(s) with the attendants while they dress. If there is a first look we try to do the bulk of formals you can do then. If someone wants to cut planned photo time because they are late (and this always happens) then that person needs to sign the schedule saying they changed it. Only the couple or the coordinator can do this. Its useful because you've got proof if you miss a picture. However I've never missed a picture unless that party missed their time.
But the real bottom line is I've done hundreds of weddings. And I know my equipment backward and forward so I can figure out a picture pretty quickly. I pride myself in feeling secure in my ability to dial in most pictures pretty quickly.