One of the ways to give feedback to a designer is by rating their designs with stars. This gives designers an indication of what you do and don’t like. Just roll your cursor over the stars below each design thumbnail image, and click the rating you’d like to give.
Pro Tip: It’s usually not a good idea to rate designs above 3 stars in the early stage of your contest. The 4 & 5 star ratings are the highest ratings that you can give, so new designers might get discouraged from entering a contest where designs are already getting ratings at that level. This keeps your contest competitive.