A marathon is a long event and to get the best out of yourself, control the controllables in advance. Make a realistic plan! One of the most important things to plan is your pacing. Going out too eager or surging too often, could be the difference between a strong finish or a painful last few miles.
Start by working out what time you are aiming to finish in. For example, if you are aiming for 3hours 30mins, then this is an average pace of 4:58mins per km. Hitting the pace to the exact second is tricky, so I would recommend setting a pace range of 3-4s either side of your target pace. For the 3hours 30mins runner, this would be a pace range of 4:55-5:03 per km. I would then break down your marathon into sections, and focus on each section at a time. Coach Steph would take on the following approach when running a marathon, spitting the run up into three parts.
The first half of a marathon should feel comfortable. You should feel like you have got plenty in the tank and you are cruising along. I would stick to the slower side of your target pace. If you are aiming for a 3hour 30min marathon, this is a pace of 4:58/km so I would not run any quicker than 4:56/km. A few seconds here or there might not feel like a lot but over the course of 42.2km, this will start to add up. Enjoy the first half and try not to get ahead of your pacing plan. Remind yourself that you still have a long way to go!
Also remember to keep on top of your fuelling plan from the get go. I would advise a gel every 30-35minutes (60g for carbs every hour).
From half way to 36k/22miles
The half way point is the real start of the marathon! This is the part that will start to test you. Breakdown the race - focus on getting to the each km or mile rather than worrying about what is to come during those later stages. If you are feeling good then gradually pick up your pace but only by ~5 seconds per km. Keep assessing how you feel and pick your moment to push on. If you aren't sure, then hold. I also like to countdown the time until my next gel and visualise this as fuel entering my body and giving me a good boost!
You've got 6k to go. It might feel like your body is being weighted down but everyone else will be feeling this too! Keep ticking off the km's and give it everything you have got. Use the energy from the crowds and focus on runners ahead of you, can you pick them off? When it gets to that final km, give it your absolute all to cross that finish line and celebrate when you get there!
Good luck, go smash it!