Slightly more verbose version: You will be better served on a career-ROI-per-hour-invested-basis in talking to people, particularly people with hiring authority, versus learning any technical skill that I could hypothetically name for you.
Having at least one portfolio piece wouldn't hurt you, but talking to people wouldn't hurt you either. Remember, the first question you're going to be asked in an interview is something like Fizzbuzz, designed to separate you from the ~90% of candidates who cannot code a for loop.
[Edit to add: Don't quit college.]