1. Clean brake track thoroughly (denatured alcohol, acetone, or simple green all work).
2. Make sure your pads are clean and not glazed. (glazing is an effect of overheating and makes your pad look "glassy" or "shiny". This will greatly effect your braking performance and cause noise). If your pads are glazed, just resurface them with some fine-grit sandpaper, and clean off with a damp cloth.
3. Make sure your pads don't have any embedded road debris.
4. Properly toe your pads so the front of your pads engage just slightly before the entire pad.
5. Properly center your calipers so the pads engage the rim at the same time.