Write a thread in the New Projects section first.
Follow the template and fill in the information. We do not offer hosting for member projects here, so if you have a demo OR a completed game, upload it to a mirror site such as Savefile, FilePlanet, Mediafire, Megaupload, etc.
Be sure to use an appropriate name for your thread, a simple format would be
[Engine]Game Name
With Engine being the maker you used (GM7 = Game Maker 7, XP = RPG Maker XP, RM2k3 = RPG Maker 2003, RM2k = RPG Maker 2000, VX = RPG Maker VX).