Training for my FIRST marathon

Good for you!

I don't know how much prior running experience you have, so don't know if this will be helpful. I've done quite a few half marathons, but only one full.

I think marathon success primarily depends on two things - (1) putting in the training miles and (2) keeping injury at bay.

For me, being fully committed to the training plan and doing my long runs with a training group was helpful. It was nice not to log all those long runs by myself.

Overuse injury is always a risk when you ramp up the miles. Cross training was helpful to me in the early part of the plan, but once the long runs got into the high 'teens I needed to give that up. The value of truly resting on non-running days outweighed whatever core fitness improvement I was getting by swimming, biking, etc.

One other tip. I got very bored of listening to music. Podcasts were a great way to engage my brain or entertain me during those really long runs.