Personally, I just get a good nights sleep and go for it.
Having a comfortable car and a decent sound system also helps. Basic amenities like cruise control, A/C, and sunglasses are also a must. Tinted windows are a bonus.
Apart from the above, eat well (skip the McDonalds and other crap), stay hydrated (not too hydrated, because that's annoying) and stay alert. When you stop every 5-6 hours for gas, walk around a bit, grab a light meal, and keep going.
You got dis.