To break up with someone,that's if you must,then these ways may be applied;
Be annoying: Do things you know your partner hates...Forget his/birthday....Use phrases or words he/she hates and maybe they will become tired of you and decide to dump you.
Talk things over: This is probably the best and matured way to handle the issue.Invite him/her and tell the person why you think your relationship isn't going to continue.Be honest with the person.
Make an audio or video CD tape: That is a romantic way to break up and you will leave better impression to your ex-partner. There are a lot of songs that you can include and all of them will say that you want to break up with him or her. However, there is a serious chance that your partner will not get the message.
Start dating her or his friend. That is probably the most effective way to break up, but have in mind that you will make the relationship between your partner and his or her friend really bad. On the other hand you will not have to think of some reasons, why you want to break up with her.
Tell someone to tell your partner that you want to break up. However that is probably the most pathetic way to break up with someone and my advice is to use it only if you haven’t been able to succeed using all the other methods for breaking up, but have in mind that even e-mail breaking is better.