A red-eye flight is any flight departing late at night and arriving early the next morning, hence the term "red-eye" derives from what your eyes look like once the fatigue sets in. And for many travellers, they'll still have to go about their day without sufficient rest once they reach their destination:
A thread on Quora offers plenty of tips to help you avoid feeling like crap once you touchdown. Most tips revolve around making a few adjustments to your eating (and drinking) schedule.
Eating dinner early (especially before arriving at the airport) to help your body adjust to its temporary new bedtime. You can also try to reset your sleep schedule faster by fasting or finishing eating for the day way earlier before your flight.
But most important of all is making sure your body stays hydrated since you'll be spending quite some time exposed to the dry cabin air. This is essential in order to feel more rested once you land:
Drink LOTS of water. [...] Grab more water onboard if possible - dehydration can make you feel more tired, then as soon as you get to the terminal, grab a coffee for the journey into town.
For more useful traveling tips like using melatonin to sleep better and fitting in exercise at the right times, check out Quora.