
In your checked bag, keep a fresh change of dry clothes (including underwear, socks and a comfortable pair of shoes) for after the race, as well as a healthy snack that includes both protein and carbohydrates, to help you recover. For competitive runners, planning not to run with you phone, credit card, and ID makes most sense, so you if you are running for time, you can put these in a small bag inside your checked bag to obscure them and use them after you cross the finish line. If this is your very first race, you may like the comfort of your fundamentals. In which case you'll need a fanny pack that you've used before, and you are familiar with.
Make sure you’ve looked at any race day programming online and know schedule updates. If the race starts at 7am, you may need to be in your corral as early as an hour before that. Leave extra time to check your bag, use the restroom, and do any warmups and activations. When you get to the start, go straight to bag check and then the restroom.
Next, you’ll want to do a short warmup; yes, even before a marathon! At least a ½ mile to one mile of very light jogging, along with some strides to open up your hip flexors, and get your legs firing, will help your body to be ready for the start! Also, some activations and drills like leg swings, knee pulls, tabletops and quad stretches provide an important preparation phase.

Get into your start corral on time and make sure you stay warm. About 10 minutes before the start, plan to remove your warm throw-away layer and deposit it in the consignment bins (if available).
Finally, enjoy your race! Pace yourself according to how you've trained. Don’t go out too fast. Focus on your own pace. Do not get caught up with how others around you are running. Trust your training, and celebrate all the hard work that got you to the starting line!
Photo Credit: 1. Background, Starting line by Chelsea Beasley @chelseabeasley; 2. Race day gear by Chelsea Beasley @chelseabeasley; 3. Runner (Chelsea Beasley) by Jason Suarez @notafraid2fail