Q. Dealing with my little sister has always been a problem, but now I feel as if I could jump off a cliff, screaming about how much I despise her.

She always finds those things that get on my last nerve and then she picks at them until I just want to sit and cry. At other times, though, I become abusive and explosive. The odds are definitely against an 11-year-old who's in a fight with a hotheaded teenage boy -- since I can bench her weight -- but she can still pick at my mind way better than I can pick at hers.

But here's the worst part: My parents have either given up or they have just let her off easy from the start. They never believe me when I say I need to get help, but if I don't I feel that I'd die just to get rid of her.

All I'm asking for is a list of ideas to help me deal with this demon before I do something that I'd regret.

A. Though your parents may not recognize the seriousness of your situation, your school counselor certainly will.

Go to her, on the double, and if she's not available, call the mental health number listed in the front of your phone book and see the person they recommend.

Talk candidly with this counselor and ask her to talk with your parents, too. They need to know that you and your little sister are in a deep and serious war and that the family needs the help of a psychologist or a clinical social worker to defuse the situation.

This is key. If one person in the family changes -- even 5 percent -- everyone else will change, too, at least to that extent.

The family therapist probably will talk to the four of you together for the first few sessions, and then individually and two by two so she can understand your relationships better and how to teach each of you to change the way you act.

There are other ways to bring harmony to the family.

You're smart enough to know that you should never hurt your little sister, but if you're provoked enough you may do it anyway, because the impulse center in your brain won't reach full maturity until you're 25. In the meantime, try to minimize your anger so you can avoid any more abusive, explosive behavior.

To do this, start acting in a positive way, instead of reacting negatively.

When you see your sister wear a pretty outfit or come home with a great haircut, tell her so. Let her know whenever her appearance, her artwork or her soccer game is better than usual. The more you smile at her, compliment her and ask her to play an occasional card game, the better she will feel about herself and the less she will need to pick at you.

Otherwise she will keep bugging you, but don't blame your fights entirely on your sister: It takes two to play this kind of emotional Ping-Pong. When she slams, however, you don't have to slam back.

Although your sister knows that you hate for her to pick at your mind, she's going to go right on picking if that's the only way she can get you to notice her. An 11-year-old (or a 7-year-old or a 15-year-old) is like a 2-year-old. She would rather have negative attention than no attention at all.

The way you handle sibling rivalry now, however, may decide how you will handle all rivalry for the rest of your life. If you and your sister keep exchanging hateful digs, you're more likely to use these same mean techniques when you grow up.

But if you learn to get along with her in your preteen and teenage years, you will become the kind of adults who marry for life, enjoy their children -- even when they get hotheaded or tease their big brothers -- and who like their grown-up siblings, too.

You may even find out that you like each other already.

Questions? Send them to advice@margueritekelly.com or to Box 15310, Washington, D.C. 20003.