Tips for painting old walls?

I am a 19 year old college student and I don't have that much experience with painting walls. I am moving into a room in my sorority house and I want to paint the walls a different color. The house is in good condition for what it is since it was built in 1812. My room just happens to have walls that are not the best. There are tiny holes from previous nails and thumb tacks. I just wanted some tips about painting. Do I need to spackle the walls? The room is now purple and I want to paint it hot pink. Do I need to paint the room white first? I need some tips please!