need to prove myself

I have started a conversation with a girl a long time ago, did all those things that I came to know I should not , like entertaining her , starting the conversation everyday ,starting with boring texts, and so on. I've realised that she was not interested in me and didn't message for months. Now, as I have your support, I want to chat with her again and prove my worth . How can I start again after several months and prove myself? Please help me