My dear friend ran a wedding business 1955 to perhaps 1980. He had on average 5 photogs working for him and they all did 2 or 3 weddings a weekend. Started with two Voitlander Prominents and the RF`s self destructed in a month. Got Leica 111F until until the M3 came out.
He would tape them and resell sell them every year. His shots were 85% 50 mm, a few 28, the rest 35 and 90 4.0. Braun EF3 flash units which put out light like a flash bulb, infact they look just like a satin reflector and bulb. Absolutely wonderful light. Hold it high with the left arm. 10 feet was f8, seven was 11, 13 was f 5.6. Did not have auto exposure flash.
Each man had two cameras which he checked out Fri, returned Sunday. Basic 35/50/90. All were trained how to pose, focus and expose. To this day the pics are stunning.
He got the formals hand painted from Opal G paper if people had money. The was a pro who did this for him.
He got 100 foot rolls of film by the case. 44 exposures went into the brass cassettes.
Table shots were done on factory rolled film.
Attention to detail got him a big enough business to put put 3 children thru Northwestern University which is an expensive private school. Today it is $50,000+ a year.
So here is the thing. Detail, learn to light with whatever is available today, Braun EF3 are still the best but long gone, process your files carefully. You don`t need ISO 3000 and fancy zoom lenses. Quality basic lenses are fine. Learn to pose. Repeat learn to pose, Learn to light, photography is all about light. Have back up equipment, check it all long before every job, things like flash sync.
Don`t work cheap. Good equipment is is expensive. Your time is valuable. If they want a cheap job, they can let Uncle Bob do it with his Canon Rebel. But have albumns to show why Uncle Bob can`t do what you can do. If they can`t see the difference, just let Bob mess up the wedding.
Work with some other locals so you have back up in case you get the flue.
Have a place to stach the back up gear.
I want to wish you luck because I could not do this, but that is what is required.
Hone your sales skills so you get the job.