When basting a quilt your backing and batting should be 6 to 8 inches bigger than your top. Center your top, leaving the extra fabric on the outer edges. This way if you have some slippage, the back and batting will still fit. I like to tape the backing down with painter’s tape or masking tape, this will keep your backing taunt. Pins, pins and more pins. Start with pinning down and across the center of your quilt, then pin diagonally, use your fist to ensure you have enough distance between each pin. Don’t skimp on pinning, this will keep your top, batting, and backing in place.