Of course, just because all breakups are painful does not mean they all hurt the same. Here are a few suggestions for minimizing the hurt (note that these suggestions assume you are not on extremely bad terms with the person you want to break up with):

1. Make the decision up in your own mind first. If you really want to break up with someone, set your mind to it beforehand, because if he or she still has feelings for you, he or she will probably protest and try to win you back. You don't want to get caught in that situation. Make up your mind first. Be certain that you want to break up with him or her before you actually do. When you end a relationship, the romance between the two of you is almost always over. Couples often get back together, but when they do, it usually isn't long before they break up again. So make sure you're certain.
2. Don't give him or her hope. You're breaking up because it's over, right? So don't tell your ex anything cute like, "Maybe it'll happen again some time," or, "If it's meant to be, it'll still happen." If you think it can "still happen," you shouldn't be breaking up. If you're just saying that to be nice, realize that by giving him or her a false sense of hope (which you are doing) you will hurt him or her much more in the long run. You will cause more pain trying to be nice. Don't. Make it final.
3. Do it in person, privately. Don't call. Don't write. Don't do it in front of everyone. Show him or her that you care enough to tell him in person, privately.
4. Don't expect to be friends right away. To lose the person you love really hurts, and guys take this just as hard as girls-- and, if you're his or her first, he or she might take it even harder. Now many couples plan to stay friends-- and that's great-- but give some time and space. You need to get over each other. Respect that.
5. Don't start dating someone else right away. Not only will this hurt your ex, but this will hurt the new person, too, because you probably aren't going to be over your ex in such a short period of time. It's not fair for a new boyfriend or girlfriend to have to deal with your old feelings. Get over your ex first. A period of two to three months is usually sufficient, but only if you feel you're really over him.
6. Don't snipe at each other! If you try to get revenge, he or she will strike back, and then you will retaliate, and he or she will respond to that... Don't get caught in that cycle. If your ex acts like a jerk, don't worry about it. Let the person go. It's over. You're away from him or her now. You don't have anything to prove anymore.
7. Again, do be absolutely sure you want to break up before you do it. Few things in life are as painful as being dumped and then being told, "Well, actually, I want you back."

Now the above suggestions only apply if you still care about each other, and you treated each other right. If abuse was involved, the situation is much different.

There is no need to retaliate. If your ex spreads rumors about you, only idiots will believe them. There's no need to get upset and try to fight to save your name; often, if you do, people will only think you're trying to cover something up. So let it go. Striking back will only draw the pain out. Besides, the people that really do care about you will take the time to get the facts straight, and the rest don't matter.

Usually you can handle things on your own, or with the help of your friends. However, there is one situation where you do need to seek help. If he or she seriously threatens you-- or if you're not sure whether he's (she's) serious-- you need to tell someone. Yeah, it may seem embarrassing, but don't let it be-- he's the one that's done something wrong, not you! There is nothing you can do that makes it "okay" for anyone to threaten you. You having to live in fear is never "okay."

Who can you talk to? Hopefully your parents can be of help, but if they're not available-- or they won't listen-- ask a teacher, a religious leader, a friend's parents-- heck, anyone you can, just someone that will listen and will see to it that you are protected. If it's really serious, call the police. Don't be afraid to ask for help.