When someone hasn't really succeeded in making themself look hotter, more likable, or intelligent. They only slightly have improved and could definitely do better. For example, if one takes a thirst trap on snapchat, but didn't really improve their look and nobody slides up, they have only gone from an 8 to an 8.3 and need to do better.
Girl, that thirst trap was not it -- you went from an 8 to an 8.3. You can definitely do better