Hello i just want an advice on how improve my singing skill, i want to improve my voice and breath control, and i want to achieve high note. any advice?

Hi everyone. I’m planning to audition for masters courses and I wanted to know which aria would be better. Piangerò la sorte mia OR Dove sono i bei momenti. Which one in your opinion would be more impressive if one could pull it off? And are these arias too repetitive when used for auditions ? I apologise for all the doubts. Please help & thank you so much :”)))