The personal uses i know about sugar are these, but i am not sure if there are more of them or not, but be sure that other people will leave comments as well so you can collect all of the uses together.
Sweet substances, by its various forms, has been used in traditional spells to sweeten up someone to see things your way for centuries. Sugar, whether white, light brown, dark brown or raw, in crystals or in liquid cane syrup such as Karo or Golden Barrel syrup, is the most economical way of using this substance when you want a lover to see you, get a boss to give you a raise or to attract money to you or bring in business like bees to honey.
Just like honey, it too, is considered a necessity when you are creating a honey jar spell for love. I don't know if you have heard about the honey jar spell, but i am sure it is brought to attention in alot of spell sites, perhaps you will see this kind of spell here as well.
In the majority of different spells that are passed down by tradition, one sweetener like sugar can be substituted for another and you can custom make your jar spell by using white sugar or Karo syrup if the person you want to get into their good graces is Caucasian, light brown sugar or honey for a Latino or a light skinned person of African descent, and dark brown sugar or molasses if the person is a darker brown person of African races. For me sugar presents love and sweetness, since it is a sweet thing, so most likely it is used in the spells i told you about.
It would Be great to hear about other uses for spells from other members as well...