There is a smart and a stupid way to perform a psychic attack on someone.
The stupid way is to go on an all out attack out of hate. It is generally ineffective and self-destructive. Hate is closely related to closed-mindedness, and as a psychic you want to avoid being closed minded at all costs.
The smart way is to realize that destructiveness is as much a proper way to handle things as creativeness. You don't want clumsy psychic attacks; you want probes and precision cuts.
Generally a well executed psychic attack is an act of healing which empowers you. If you want to hurt someone because you think they deserve it and it is the best thing you can do for them, well, you might be right and you might be wrong - it's better to be honest with yourself.
A healing psychic attack confronts the person you are attacking with his or her fears. This is one of those cases where it gets a lot worse before it gets a lot better. The general process of a psychic attack begins with finding out their fears, resonating your own psychic energies with the 'frequency' of their fearful psychic energies, amplifying them, and lastly unleashing these energies.
If your intent was simply to hurt, that is the end of the process. If your intent was to heal, you should stick around and help put the pieces together.