Put sugar and water on the stove and bring to a boil, stirring occasionally. When it reaches boiling point turn the stove off and let the mixture cool completely.
You could double this recipe so you could fill more than one feeder and still have some left to refill.
I just store it in a quart jar with the lid tightly screwed on and keep it in the refrigerator, until I need it. I keep it approximately three weeks. We have several feeders so we go through a lot of it.
Fill your feeder, leaving a small amount of space at the top.