PR specialists in the corporate world drum up publicity for companies, guide employees in answering interview questions, act as the "voice" for particular products or organizations, and field inquiries from reporters and the public.
If you're wearing a themed sweater - say, one with a particularly holiday-worthy pattern or a cartoon character - you might choose to wear that to a party to drum up some laughs or start some conversations.
Cold calling can be an effective way to drum up interest in your service, but be prepared to have to make a number of calls before you find a company interested in discussing the matter further.
There's always someone celebrating something, so you're sure to drum up business if your services are good.
Placing meaning behind a task such as letter writing can help drum up the passion and motivation you may be lacking for the cause you are currently trying to write about.