Commit and sign up.
Pick a training programme from the hundreds available on the internet. It doesn’t really matter which one, it only matters that you actually do one.
Adjust your diet. Sweeping changes probably aren’t sustainable initially, so maybe pick one or two things that are currently killing you (e.g. sugar, alcohol) and think of practical ways to reduce your intake of these.
Find others who are already committed to doing what you are doing and team up with them.
Use your calendar to schedule your training sessions.
Embrace the fact that doing a training session badly is infinitely preferable to not doing one at all. Perfectionism is your enemy when progress is your goal.
Do the training session on the cold, rainy February night when you’d really rather not.
You’ll find yourself reading articles or even books about or by elite runners. This is fine, and can help, as long as you remember that doing a bad training session is infinitely more helpful than reading about someone else’s perfect one.
Be polite, but ignore all the advice given by people who haven’t actually done it. They may well be giving good advice, but you have limited amount of advice-following-capacity so make sure it’s used up on the tried and tested stuff.
In contrast, take all the encouragement you can get from every source going.
Let people know what you’re doing – as long as this never takes the place of actually doing it.
Show up for the race.
Take it slow and steady.
Suck in the encouragement from all the crowds.
Keep moving forwards.
Take on all the nutrition that’s offered to you.
Become neither discouraged by the people that are overtaking you, nor proud about the people you’re overtaking.
Make use of pacers, but only in so far as they help you get to your goal.
Keep moving forwards even though it hurts.
Maintain a sense of humour.
Don’t allow the fact it is going differently to how you imagined it going cause you to quit.
Focus on getting to the next marker in front of you.
Remember, many have finished this race before, and many more will do so.
Walk for a bit if you have to, but keep moving forwards.
When the finish line is in sight, reel that baby in.