Are you a freshman?
There's no magic skill "test" that will tell you what you're best at.
Pick a major according to this:
1) What are you good at? (writing, math, music, acting etc)
2) What subjects interest you most?
3) What current skills / hobbies / interests do you have?
The only way to pick a major is to keep trying courses in different fields of study until you find the one you like the most, or hate the least as it may be. I LOVED movies and cinema. I went to USC hellbent on studying to become a film editor. I left 5 years later with a degree in Psychology, after burning through courses in Computer Science, Business, Theater, Music, and Philosophy. You never know what you "click" in until you try.