The best way to get anyone to listen to you is to start out by being calm and assertive. You might try meeting your parent at a neutral place. For instance, try talking over a meal out at a restaurant or at a park. Next, make sure you know what you want to say and can support your ideas clearly. Be sure you consider their point of view as well and be prepared to listen and respond to their perspective. Try to have a calm conversation without being emotional or accusing towards the other person. It may help to write out your concern and any important points you would like to make. It may also help if you allow the other party a chance to process your request before having the conversation. For instance, you might request to talk about a specific subject at a designated time in the future. Most people don't respond well to being put on the spot. It helps to have time to think things through before entering a potentially difficult conversation. Finally, be prepared to compromise. Parents just want what is best for their children even though their children might not always agree with their ideas.
Be rational. Talk things through with them and understand their views and reasoning just as you want them to understand yours. Be willing to make compromises with them.