In the Challenges, you'll see ghosts of your friends. Simply beat their scores 30 times to earn this trophy. Each friend counts as one towards the trophy, so the more friends you have doing challenges the quicker you'll obtain this.Furthermore, you can also create a second profile, add that profile to your friends list, and then have that profile score very lowly, making it easy to overtake its score.Thanks HappyKastanie for the tip regarding a second profile!