Most people attempting a marathon for the first time would do something smart like consult a trainer or join a running group. I prefer the do-it-yourself approach, since trying to get coordinated with other people would eat into the time I have to actually train. So I read dozens of plans and articles about plans and rolled my own...
It's basically spending summer carefully building up to running the kind of mileage most serious runners have before they even start training, and then carefully doing increasingly long runs on the weekend, backing off a bit after each milestone.
The serious runners will probably be aghast that there are only 3 running days each week, but that's the time I have to do it, so that's what I'll do. Just for them, there's a proper 3-week taper at the end.
Non-runners will probably be aghast that it takes around 600 miles to train. Luckily it provides the answer to the age-old question of what do I want for Christmas? This year, it's a new pair of shoes.