For my first (an almost certainly last) marathon. I got in involved in a training group. Being with a group is really a good way for sedentary folks (like me) who dislike exercise to get the discipline to complete the training.
If I was going to do it over again, I'd join a charity marathon training program, like
Team in Training.
Basically, how this work is you raise $X amount of dollars for a worthwhile cause
Leukemia b(but there are many others) by getting sponsors. They give you training and if you raise enough money will even pay for your trip to Honolulu. What is so nice about the program is you are surrounded by non-runners.
BTW, the Honolulu Marathon is very nice marathon about 1/2 the entrants are basically walkers (like myself).