Here's a simple recipe for hummingbird nectar:

The basic recipe is four parts water to one part sugar. You may find that the sugar crystals dissolve best in boiling water. Remember to allow the water to cool sufficiently before hanging the feeder back in its position outside. Any left over sugar-water can be stored in the refrigerator for several days.

Nectar should be replaced once a week if possible and more often in the summer, though depending on the climate, you may be able to get away with only replacing once every few weeks. It's best to locate the feeder in the shade. Always clean your hummingbird feeder with mild detergent and rinse thoroughly each time you replace the nectar.