This girl i loved broke up wiht me cuz she still liked her ex, now shes moving on i want her back really bad?

shes a year younger, and she was the first girl ive ever been in love with, we started out great like we couldnt be without eachother, now she brok up with me cuz she has feelings for her ex but she likes this other guy whos way more popular than me. everything i do to try to get her back is just annoying her, ive written letters drew her pics. how can i get her to like me again, i just wnat to be back in a relationship with her, any help pleaseeee?