Using a dark colored background helps the flakes to stand out more. I've tried a variegated scarf and the colors were interesting but I felt like it takes away form the intricacies of the snowflake a bit. Also, if the background has texture, like a wool mitten or a knit scarf, the fibers give the flake something to land against.
Tip 3: Look for Light
When the snowflakes land on one of their tips, propped up against a fiber from your backdrop, you have opportunity to move around it, looking at how the light effects it's sharpness and shape. Play with angles to see how the light and shadow bring out each angle in that snowflake.
Tip 4: Just One