Know-How Exchange : Career/Training

You should understand what sort of work the agency does. Are there similarities in who they have as customers - from certain industries, etc. Do they have a specialty in the type of marketing they do (online, offline, market research, etc.). Do they focus on certain geographies? Then be prepared to address how your experience or education can help for each of these areas of specialty.

Of course, also good to understand what they expect from a person in the position you are applying for - what the duties will be and such. Also be ready to talk about how your experience and education match the job's duties.

You'll notice I didn't talk about what areas of marketing are good to know, as you had asked. But instead focus on what the company does as the guideline for what you should be researching.

1) Know the agency and their clients
2) Know what YOU believe about marketing and be able to clearly communicate it. There are differences of opinion in the market and you'll be happier at a place that agrees with your philosophy.

Michael