1. For jeans or khakis, try a 1 to 1.5-inch cuff, doubled. You'll want to adjust cuff size to pant length to avoid the Victorian knickers look.
2. If the fabric is loose around the ankle, rein it in with a subtle taper. You can do this by pinching the fabric at the seam and doubling it over before performing the roll.
3. Give the cuffs a squeeze, a twist, and a gentle pull to rustle them a bit. After all, this is supposed to look like it was done in a hurry.
Find more tips on flair below the knee here.