One part green tea (home brewed, not the bottled stuff), one part orange juice, two parts water, pinch of fine table salt, pinch of potassium chloride (sold as NoSalt and several other "salt" substitutes). While preventing electrolyte imbalance is important, the vast majority of what you hear about this drink, or gel, or what have you being superior is 99.99% marketing hype. A small amount of sodium chloride (table salt) and an equal amount of potassium chloride (NoSalt) in any drink is sufficient. I like the above mix because it has a small amount of sugar and just a bit of caffine.
If you do use Gatorade, Powerade or the majority of sports drinks, dilute them at least 50:50 with plain water and sip, don't every guzzle.