First of all, let me say that anyone can do it if you put in the work and dedication. And second, it’s going to be awesome and awesomely painful! Now you know! Do you still want to do it? If yes, read on.
Endurance: You will need to do your dreaded long runs at least once a week. I did 10 to 12 miles every weekend for a few months, tapering for the last two weeks because I didn’t want to overtrain.
Nutrition: You have to eat well if you want your body to perform. Eat plenty of good carbs like sweet potato, zucchini, quinoa, broccoli, rice, oatmeal. Don’t forget protein like chicken, beans, nuts, yogurt, protein shakes. The day before the race pay special attention not to introduce new foods. You want your body to respond in a familiar way. 
Your dinner should be a substantial one so that you will feel full all night and not wake up ravenous. In the morning, drink water, coffee, tea (whatever you need to help you with… ahem… moving things along so your stomach will be empty). Then one and a half hours before the race eat some simple carb like bread, and protein like yogurt (whatever works for you to give you energy while being easy on the stomach). For me it was peanut butter and jelly sandwich and a yogurt. It kept me full the whole race so there was no need to reload. And at the same time it was so gentle on the stomach that I had no issues that some runners experience during the race.
Strength training: Let’s remember, strong muscles move better, faster, last longer and get injured less, so don’t neglect it. I trained my legs, upper body and core three to four times a week.
Speed work: I did my tempo 5 to 7 mile runs three times a week. You might ask why would you need to work on your speed if you are doing a long distance race. It’s actually very simple. Aside from the fact that we all want to be faster and do our best, it’s also important to note that when we do our tempo runs we use different muscles(fast twitch) versus when we run for endurance(slow twitch). Being able to switch back and forth during your race can be very helpful in preserving your muscles and avoiding injury.
Prep work: This includes stretching, foam rolling, massaging, physical therapy and whatever else you need to get those muscles loosened up and ready to do some hard work. Don’t neglect this or you will regret it come race day. I had a tight hip that was bugging me for a few weeks. If it wasn’t for my very awesome Physical Therapist, there’s no way I would have been able to run my race and do as well as I did. He was able to identify what was the problem and helped guide me on how to fix it (which I did ad nauseam!) 
Apparently, my left hip was not as strong and was lagging behind causing tightness and pain that went all the way down to my calf. In my case, I had to work on strengthening my hip with some very specific leg raises, stretching my hip flexors and foam rolling, foam rolling, foam rolling until the tightness was completely gone (I love you Scott, this race was only possible because of you!)
In conclusion, anything you want will require hard work but if you want it, it’s worth all the time, effort, pain, sweat and tears! I finished 25th among women and 2nd among women my age. Yes, I would say all the work was well worth it and I would do it again!
