The worst thing you can do when you are receiving a bad report card is to allow your parents to be surprised by it.  Tell them before they receive it.

Since it can be hard to confront parents about something that you know will anger them, schedule a time to talk to them when you know they will not be irritated or rushed.

Admit that you made a mistake. Taking responsibility for your actions is a vital step.

Do not blame anyone else.  Saying that you failed because your teacher hates you, is likely to anger your parents.

Act like an adult.  You should approach this situation like an adult and your parents will be more likely to listen to you calmly.

Control your emotions!  Screaming at your parents or breaking into tears when they say they are disappointed (which is nearly inevitable) will only make them treat you like their little boy/girl. 

Explain how you plan to rectify your errors.  Provide a plan, preferably written, to elaborate your intentions to improve for the next semester.

If possible, provide evidence of your improvement, such as a recent test or paper where you scored much higher grade.

Be prepared for punishment.  Your papers may still punish you and the best way to handle it is to accept it and apologize for upsetting them.  If you fight them, the punishment is likely to increase rather than go away.

If you want your parents to respect you, show them respect.  Listen to their opinions and advice as well as giving your own.  Try to negotiate and come to an agreeable resolution for everyone.