I don’t think that the color of the light is going to change much about the harshness of it. What you need to do is diffuse the light.
For example, if you’re shooting outdoors in sunlight, try having someone hold a white sheet between the sun and your subject. The sunlight will be diffused through the sheet, and make nice bright even lighting that will make soft shadows, not hard ones.
If you’re indoors, try bouncing light off of a white wall or ceiling. If you’re using external flash, it’s very easy to point it at a white substance, or put a piece of paper in front of it to diffuse the light.
You can even diffuse your on-board flash if that’s all you have. I’ve used copy paper, or even Kleenex to diffuse my flash! 🙂