It's really hard to say with such limited information. Do these 2 people live close to one another? Attend the same MA school? Same high school (because that what it sounds like)? Can she avoid this person without it being obvious? Is the other person an accomplished fighter? Having been the big guy that all the punks with "little man's syndrome" decided to try their luck with, I have a little experience in this matter. If she "has to" fight, have Jackie make it on her terms. Advise her to pick the time and place and to be the aggressor. Not one of those "Meet me here at 1:00" deals. I mean that she needs to make up her mind and just do it. When she's ready, she needs to go up to whoever and just do it. No mouthing off or saying I'm going to kick your butt. Just kick her butt. 9 times out of 10 whoever gets the first good strike in wins the fight anyways. Keep in mind that it is always best to resolve matters peacefully. However, if that cannot happen, then Jackie needs to control the situation. Make the decision to fight, decide when it will happen, be the aggressor and strike first.