Tools Needed: comb, sharp scissors, and a swing-arm chip clip (Pampered Chef was the first place I saw this kind, but they're at Kroger and other places now)
Use the comb to section off the hair you want to cut. I sort of part mine in a wedge (think of the opposite of a widow's peak). Then clip your bangs with the chip clip. Slide the clip down the hair to the desired length. Clip with scissors.