Having some knowledge would be great for you but personally I'd focus on the basics and primarily concentrate on knowing all you can about the foreclosure process and short sales.  For background:  I have worked in real estate, was a loan officer, had a company that bought pre-foreclosures and lease optioned them and obviously have dabbled (ha) in abstracting so my BREC (blood real estate content) is pretty high :).  Learn how to work with the banks' loss mitigation departments, learn their language.  You will have a huge advantage over your competition if you can help your sellers negotiate a short sale and you'll have an easier time with buyers buying a short sale.  Learn how to deal with REOs. 

I think everyone here would agree that the foreclosure market is still going strong if for no other reason than some states (like NJ and NY) taking 3-4 years to foreclose.  So many agents try to market themselves as being experts in REOs and short sales but I've learned from personal experience they've only learned that's a good advertising gimmick.

For once I agree with George, and always with Alix.  Be the best agent you can be.  Be tech savvy as possible (enlist a young person for help if you're not up to speed).  Use a contact management system (CRM), make sure you keep up your database, send quality informative email campaigns  - not the generics everyone sends, find good short articles to put in a bi-weekly email.  Keeping up your database and staying contact with your buyers takes diligence.  Be creative in your print marketing so your piece doesnt look like every other agent's.  I suppose I'm proselytizing here but I was also formerly internet marketing director for a real estate website company and my fiance is a successful loan officer who utilizes all these things and more.  Also, find one or two loan officers who've been in the business for over a decade and if you're lucky, find one who has a lot of this type of marketing at his/her disposal and knows how to use it - they'll be happy to help you market yourself and you won't be paying out the wazoo.  My fieance uses a cool phone app he gives to his agents called LenderApp.  It's co-branded with the agent and allows the agent to give real-time rates using FHA or Conventional options to allow their buyers to see what they qualify for.  They keep coming up with nice new free upgrades too.  If the buyer is shopping for a while, his agents give the app to the buyer so they can use it any time and presto - the agent's face is there every time!