1. Coffee. Do not chug the coffee. Do not drink pot after pot of coffee. If you do this, it will burn a goddamn hole through your stomach. And you will crash. And you will be miserable and exhausted and nauseous. Don't do it. Moderation, y'all.
2. Water. Keep it coming.
3. Snacks. Do not go for sugar for a quick boost. A quick boost leads to a quick crash. Choose protein. Hummus, peanut butter, cheese are good, and pair well with veggies. There'll be a temptation to snack in sheer desperation to keep yourself awake. Keep the fruit and veggies on the table, not the cookies.
4. Have someone checking up on you and making sure you eat actual meals, if at all possible.
5. You know the standard writing advice? "Butt in chair"? Do not follow that advice during Blogathon. If you keep your butt in the chair, you are going to fall asleep. Hit post, then get *up*. Stretch. Quick bit of yoga, if you do that. Dance. Do not be a slouchy exhausted lump. Keep your body in motion.
6. Meds. If you have medication that you take before bed and/or upon waking, keep in mind that you are not going to have those usual cues - set the alarm on your cell phone, or a popup on your computer.
Any advice from anyone else? Any questions? Good luck!