Create
50 Achievements
PS3
Top Marks
Mark another user's content as one of your favorites
7.4%
How to unlock the Top Marks achievement in Create - Definitive Guide
BJFindlay
TrueAchievements
TrueAchievements
Edit: As of April 13th, 2012, EA is shutting off the server and this achievement will be no longer obtainable.
From the start screen:
1) Press Y to bring up menu
2) Press RB to bring up Menu & Online Features
3) Press the one that says "Community Challenges"
4) (Press accept) Press Y to View Entries
5) Choose any of the boxes, select one and press X to favourite it.
From the start screen:
1) Press Y to bring up menu
2) Press RB to bring up Menu & Online Features
3) Press the one that says "Community Challenges"
4) (Press accept) Press Y to View Entries
5) Choose any of the boxes, select one and press X to favourite it.
Bryc10
No longer possible due to server closure.
Pretty self explanatory, visit the EA Online Gallery by selecting Community Challenges, select a Community Challenge, then press triangle to view entries. Look at the entries and select another user’s creation, select view which will load the creation.
Once it has loaded, go to your options 
and go back to Community Challenges, you will now be prompted to rate it. You can also press square to add it to your favourites. Once done press 
to confirm and continue.