what to do?

O.K i am going to High School in the fall (9th) and I dont know how i should act , dress ,talk, or make someone outta myslef… i wanna stand outto this 1 guy who i really lk an is my EX but he already promised me tht we would get bac together….. but i dont want the chance of losing him?… i dont wanna change for him I jus want him to lk me more thn he does this way if we do get bac together….. he WONT look at the other girls lk most PIGS!!! do