There are several different diets you can put your sugar gliders on. While there is no "correct" one to feed, it will really depend on what you and your gliders prefer. We chose to do the BML diet as I find it easy to make (I can make a double batch in roughly 30-40 minutes including time to boil the eggs!)
Whatever diet you decide to go with, be sure to always supplement with fresh or frozen vegetables, fresh or frozen fruit, and a sugar glider specific pellet.
Pellets should be kept in the cage at all times for those random day-time munchies!
I feed them a handful of veggies (corn, carrots, peas, and green beans) along with some fruit. My sugar gliders love cherries, watermelon, and blueberries but are not a fan of strawberries or mangoes. Every glider is different so you will need to work with yours to figure out what they like and don't like!
I also give them meal worms as treats each night. They greatly enjoy them and even take them from my hand!
The BML diet costs me roughly $0.50 a day to feed two full grown, parent sugar gliders. ($50 for the initial purchase, and I get roughly 8 batches of food before I have to replace anything and each batch is at least 16 days worth).
Each night, you should feed:
1 handful of vegetables
1 small handful of fruit
1 ice cube worth of BML
3-8 meal worms per glider (or replace with another special treat)
Here is the BML diet I use: