Multiple singing problems ?

the sopranos usually have the melody on songs and it's common to want to follow the melody, especially in a song you know. that takes repetition. It's very difficult to teach voice projection and tone control over the internet, you're going to have to find someone near you to teach you. as for the audition, sing it to everyone who will listen and ask them for their opinion, ask them to be really honest. sing it over and over. good luck!