What do i need to do to get into cornell?

I had a very strong freshman year and a strong 1st semester of sophmore year but i slacked 2nd semester. I will be a junior in the fall and i really want to go to cornell, so if i go back to getting mainly As with 1 B will i have a chance? I also have alot of extra curriculars and i did 20 hours of community service both my fresh man and sophmore year. I also am preparing alot for my SATs and ACTs to try and get a really high score