I disagree on sports drinks. They are all high fructose corn syrup and refined sugars. Dextrose is good for keeping blood sugar stable. One can buy a pound of dextrose from a homebrew shop. Add it to a water bottle with a slice of fresh lemon. There is your energy gel at a fraction of the cost of the other crap.

Hydration is key. It's also important not to "carbo load" Eating a big bowl of pasta the night before is asking for a cramp. A good portion of rice and vegetables is the way to go. Taking a big bowel movement the night before would also be advantageous.

Riding with a colon full of stuff is painful and not going to make the ride easy. Eat a big portion of mineral rich vegetables. Dextrose/lime/ water is a good helpful tool.

The big one for me is stretching the IT band. It takes a lot of hip pain away from my riding that I would otherwise have.