To reduce tears: To reduce the amount of onion oils that make you tear, put your peeled onion in the freezer for about 5 minutes prior to cutting.
To dice: While many of you know how to dice an onion, this tip is safer and easier. Cut an onion in half and peel the outer layers from each half almost to the root. Do not take the outer layers off as this will be your handle. Hold onto the layers in a bunch to hold the onion half then slice vertically and horizontally for perfect dice.
To reduce cooking time: Making caramelized onions takes forever, but you can speed up the process by placing the sliced onions in your microwave.
Onion Leftovers: If you need only 1/2 of an onion, save the root half. It will last longer.