1. Print your plan & post it in plain sight. Why? So you are always mentally prepared for what's next -- especially those long runs. If it's on your fridge, you'll think twice about eating something that might upset your stomach -- and you'll remember to eat things that will help you train your best.
2. Get the right shoes. I would go to a shoe store and have them check out your stride, etc. Speciality running stores normally do that. If you've never done it, it's worth it. Some websites have shoe surveys where you can do it that way as well. Makes all the difference.
3. Buy anti-chafing gel. Trust me, ladies, you will NEED this under your sports bra. Otherwise, you will rub the skin under your boobs raw. For runs longer than 5-6 miles, I always use it.
4. Fill your water bottles with Nuun. It's light enough and provides the electrolytes you need on a hot, humid summer long run. I can feel a difference and you want to be prepared.
5. Long run post-fuel recovery is important. Make sure you plan on drinking extra water with electrolytes throughout the day, not just right after your race. Eat protein - either a shake or some kind, eggs, chocolate milk. You need something right after if you have any hope of being a normal human being the rest of the day.
6. Don't ignore speed work. I did and it's not going to kill you but it matters in helping you have a good race. You need to know what it's like to push it when its REALLY hard. Speedwork is HARD because you run much faster than your comfortable pace but it pays off mentally and physically.
7. Training right takes sacrifice. It means giving up some weekend night plans, it means actually getting up and doing it when your alarm goes off at 5:30am on Saturdays. If you aren't sacrificing, your going to have a really hard marathon. Commit.
8. Don't worry about a time goal. It's your first marathon -- your goal is to feel it out and get through it. Don't set yourself up for disappointment. Next time you will now where you are weak and how you can remedy that.
9. You can walk through the water stops. On race day, MANY people take a tiny rest and walk through every single water stop. There is no shame in that and it doesn't mean you "didn't run the whole thing." It gives you a chance to re-adjust and get your mojo back.
10. Remember that race day is 100x better than training. The day of the race, you will have fresh legs, excitement, you'll be fully fueled and you often don't need to carry your own water so it lightens the load. People are cheering you on, your wearing a number, this is the day you've been training for. It's fun and hard and totally worth it.
There are so many little things to remember for training. I could make a much longer list but I'll leave you with these bits for now (and be happy to answer more specific questions!) Make the commitment to your training and you can be so proud of yourself on race day when you cross the finish line. A few minutes later, some of you will think to yourself -- "that was hard but on my next one..." Your brain will already be on marathon #2.
Do you have other specific questions? I will answer the best I can. Do these suggestions make sense? Let me know!