#3 Leverage Recent News

If there's something in the news that relates to your product, either directly or tangentially, go ahead and make the most of it.  Often, referencing a story that's prominent in the news can get you some added attention -- especially if your ad is appearing in a newspaper (but it can work in other mediums, too.)  Tying into tragedies is obviously a bad idea, but everything else -- politics, milestones, sports, weather and local news -- is fertile ground.

#2 Tie Into Popular Culture

If you can find a connection (real or exaggerated) to a movie, TV show or celebrity that's all-too-ubiquitous in the culture of the moment, go for it.  Use the halo effect to make your product or service seem trendy as well.  (Keep in mind there's always rights and licensing issues around these subjects, so you can't just use official photos or imply endorsements that you don't have.)

1) Tell People You're Still Around

If you haven't advertised lately, is it any wonder that people would think your product (or service) had disappeared?  Few products can remain in the public consciousness for long without the (at least sporadic) reinforcement of advertising.  If you're one of those lucky few that have achieved cultural ubiquity, congratulations.  The rest of you, start drawing some attention to yourself.