In most areas banks are on top of their foreclosures and there are few if any bargains to be had. They either list them on the MLS at fair market value through an agent or participate in "auctions" that are not the same as those you used to see on the courthouse steps five or six years ago. In the areas I invest, chasing foreclosures is a waste of time. The only "bargains" out there are direct purchases from people that want or need to sell that are not aware of what the property is worth or do not want to put it on the open market.
I get anywhere between five and fifteen solicitations a week from beginners that buy out of town owner lists after attending an investing class by some investing guru. They all send the same postcard or fake handwritten letter on lined yellow paper. Save your money if someone suggests that approach.
Start talking to people at your local real estate investment association. Watch the listings as they hit the market and be prepared to make an offer within a few hours if you spot a bargain. In a large urban area, that will be more difficult because a lot of other people are out there doing the same thing and they are more experienced and likely better capitalized. It can work in smaller, less active markets.