It is our lives to live and we should do it our way. We should surely do what makes us happy but no one should ever be blinded by love. If you really love your partner and you think it's the best for you then you must marry him/her only and not some random person is chosen by your family. Though it would be highly recommended that you give it a complete thought because marriage is a huge step in anyone's life. The major decision is for you to believe and be fully committed to this eventuality.
Following are a few ways you can apply-
Find the members of your family who would be least resistant for this. It could be your mother, your aunt or your brothers/sisters or cousins. Convince and confide in them that you love your partner.
The purpose of this meeting is to establish to your parents what a perfect husband/wife he/she will make for you. You can give your partner tips on what your parents like and what they do not. It would be necessary because you don't want anything to turn them off. This does not mean you ask them to put up a fake face to your parents. The tips will only make them put their best feet forward when they meet them.
Convince your parents of your love marriage by giving them a reality check. Nothing is as convincing as reality. Give them real-life examples of happy and successful "love marriages". You can also throw in a few examples of people you know whose marriages were arranged and have turned out to be unhappy. Explain to them how being in a relationship with someone for some time before marriage is essential to judging mutual compatibility and consequently, to create a better chance for having a happy life together.
Explain your parents the importance of mutual compatibility and understanding in a marriage, which essentially needs to be gauged before taking the final decision. Compatibility is much more than castes, horoscopes, food habits, family background and financial capability. Compatibility depends on personality types, beliefs, likes and dislikes, attitude towards the relationship and much more. And these are the things that make a bond stronger between two individuals. These things can never be even gauged without spending considerable time with each other.
Tell them about the difficult phases and times that your partner helped you in. Tell them about the times he/she supported you or made you feel special or did something out of their ways so that you don't get into trouble. It’s not easy, to say the least. But at the end of the day, your parents want your happiness. You know you your parents more than anything. So, you will need to figure out exactly how to convince them by planning out perfectly.