Just because a piece of real estate is listed on the MLS, it doesn't mean that the property can't be bought for a bargain. In fact, because you're buying from "amateurs" instead of professional wholesalers, you'll have some advantages in the buying process. 

The most pronounced of these advantages is your purchasing flexibility; you can buy any of the 50 properties listed for sale in your target neighborhood, at any time, if the price is right. Those 50 sellers, however, are anxious to sell as fast as possible, and each will have different pressures on them, ranging from nagging spouses to pending career transfers to their own purchase contracts contingent on selling their property. Many of these sellers will, of course, stand their ground, and insist on a price close to market value, but a few will be so desperate to sell that they'll be willing to sell for a dramatic discount, if you can settle quickly.  

So how do you weed out the stubborn from the desperate?  

There are several ways, of course. First, screen your MLS searches for listings that have just passed the 90 day mark, and the 180 day mark, as these arbitrary standards are often used by listing agents and sellers alike as indicators that the property is not selling for its asking price. There's a reasonable chance that either the seller or the listing agent will be anxious to have the property sold, and will push the other to accept a low offer. It doesn't hurt, of course, to point out the inadequacies of the property in question, and send every possible message that you think the listing price is absurdly high.  

Another, more obvious way to screen property listings is to search for variations of the terms "motivated seller" and "make an offer." While these phrases are sometimes used with little true urgency, you can find out just how motivated the seller is by making an extremely low offer, and gauging their reaction. If they make a counter offer, you'll know they're desperate enough to dignify your offensively low offer with a response, and an aggressive negotiation can start from there.  

If these screening methods don't yield enough strong prospects in your target areas, take a look at all the listings in those target areas. Based on your burgeoning expertise in these neighborhoods and their values, do you see any that look particularly reasonable (adjusting for the property condition – see the listing agent's remarks). Start with taking a look at these, and if they appear promising, make some lowball offers.  

The trick to finding good deals when buying retail is simply making enough low offers that you find the few sellers who would rather accept an extremely low price than wait any longer to sell. However, the onus is on YOU to know what the property's "real" or "true" market value is, so that you don't confuse the listing price with the property's value. Just because a seller asks for $200,000, and you buy the property for $147,000, doesn't mean you got a good deal; the property may be worth $150,000, and the egomaniac seller had an over-inflated idea of the value and priced it accordingly.

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