The good people at All Movie Talk have been so kind as to upload a 1929 manual for film promotions. (Just increment the number after the word "ballyhoo" to get to the next one.) Here are some fantastic ways to put asses in seats:
Let local schools have at each other in a ukelele duel!
Drag a caged bear through town!
Hold a fat baby contest!
Make insensitive jokes at the expense of the mentally ill!
Send capsules of mysterious white powder through the mail!
Bribe traffic cops to distribute tickets!
Hang lingerie in your lobby!
Bring in the drag queens!
Have women in swimsuits block traffic on major thoroughfares!
Get the entire audience fingerprinted, and turn the prints over to the police!
Accuse your customers of violating the Volstead Act!