The best way to get help is to make your hack look like it's worth helping out. Don't feel like holding back information and saying "I don't want to spoil the whole story" is going to attract anyone. For my hack, I made a thread in the Scrapbox forum (Here) describing all the thoughts I had for the game, and then at the bottom said that help would be appreciated. Now I've got the starts of a team.
You can't just go around looking for help. Why should someone want to help you make your hack? Just because you asked them to? Make a thread, show every idea you've got for your hack, show what you've put into it already. Often, if you just include a note at the bottom saying that you don't have a team yet, others might volunteer to help out--that's what happened with my hack.
If you really don't want to leave it up to chance, though, you want to head to the Team Discussions forum and, in particular, the Help recruitment thread. That's what it's there for, after all.