In order to get into NYU what all shall I do while I am in high school?
What grades shall I get?
What should I do get into that university?
Are after school program necessary in order to get college credit?
My sibling got accepted into NYU a few years ago, so I'll try to give the best advice I can.
Aim for a very strong academic background. The acceptance rate has decreased dramatically over time and it was 15% for the most recent students that were admitted. With this, the median SAT score was a 1500 (for this year). Preparing for the SAT or ACT to get a high 1500 or an equivalent score on the ACT test is vital. It is also important to keep a strong GPA, preferably 3.8-4.0 unweighted which means very few B+'s or B's. They also would like to see you challenge yourself with AP/IB classes although there are not a lot of options for credit retrieval when it comes to AP scores (depending on your major/focus of studies) at NYU. Try to take 5 or more AP classes as well as a few honors classes if offered at your school. You could minimize the amount of AP classes you take in favor of other activities, but it's a bit of a risk given how selective they are when it comes to grades and test scores.
With extracurricular activities, I'm not too sure. My sibling was at a prestigious performing arts school, held first chair in the top band for 3/4 years, participated in many festivals and concerts, won multiple awards and got into competitive bands (such as All-State), did lots of gigs and volunteering focused towards jazz, and recorded several albums with well-known individuals. The thing is, he's an Economics/Math major. I think they want to see dedication towards something you are passionate about, and since he had a very solid academic background, this was enough. His focus was music in school and that focus (although he says he did not do "much") allowed him to be a worthy candidate. I think a focus on something you are passionate about is enough to set you apart versus stretching yourself out with 5 or 6 different activities and leadership positions.
This kind of goes to show that it is not VITAL to have your extracurricular activities structured towards your major or plans after high school. It may be recommended, but it is still possible to get in with something very different.
His letters of recommendation were from one of his English teachers and his AP Economics teacher. Economics helped with his major and the English teacher really loved him for some reason.
The main takeaways I would say are: Show strength in your academic abilities and show passion.
I hope this helps! Don't stress out too much about admissions. As long as you are focused, hardworking, and doing what you are love, I strongly believe you will be accepted. Good luck! :)
Take AP/IB/Dual Enrollment classes, involve yourself in volunteering and extracurriculars, and forge good relationships with teachers that can provide recommendations.