Remember, each individual friend may only earn points for you for the first time they check out a given song, picture, and/or video for the entire duration of the contest (even if it's for a different contest in for the same artist).
If your friend is trying to help you earn points while using the same wireless connection as you (or any of the friends helping you), he or she must 'Sign In' to Tunespeak. After your friend clicks on your link and checks out the content you've shared (song, video, photo, artist), have them:
Click the 'Show Me More' button
Click 'Sign-In' on the top-right corner of the artist's Tunespeak page
Sign-in with their Facebook login