This one is very easy, and really, if you play this game to any fair length, you'll most likely get it anyway. If you don't have it however, here is the best way to get it:
Build a team with Rod Woodson (CB), Lem Barney (CB), (Charlie Waters (SS), Eugene Robinson (FS). These guys are all "ball hawks". Before the game starts, go into settings and adjust the CPUs sliders to 0, and your sliders to 100. Also adjust the Interception slider to 100.
Select your edited or created team, and choose to go against the Iron Men. I know the Iron Men have Dan Marino quarterbacking, but they pass on virtually every play, as they have no star rated running back. You should get, even with 5 minute quarters, at least 3-4 interceptions. You should also have no problem running one in for the score, especially if Lem Barney or Rod Woodson make the interception.