Submitted Map Resources need to have a good description on the Hive. Map title, author, features list, short gameplay explanation, a credits list, screenshots, a changelog, etc.
A map description that only contains "Hope you like it, my first map" or "power core v3 new updates, see loadingscreen good map" will be rejected.
Suggested Links: BBcode list - Map Description Templates by -Kobas- (Requires a minimum amount of BBcode skills) - Map Description Generator (No BBcode skills required)
[Update] -Kobas-'s user templates are no longer a recommended option to improve your description - Most users cannot properly edit the template and end up making a description that just doesn't fulfill its ultimate purpose -> Being quick to check out and learn something about the map's gameplay