Here we have a Google Tech talk from 2009 discussing the different strategies of hunting for ET. As Seth Shostak points out, there are many different strategies that could be employed to search for ET. Right now we are in the 5th decade of the search for extraterrestrial civilizations and, so far, we have found nothing. One of the possible explanations for this fact could be that our preferred searching strategy is flawed. In particular, the search for ET by hunting for certain radio and laser signals from nearby stars has many drawbacks, which have to be overcome to improve our chances of success.
Of course there are other strategies of hunting for other civilization, such as studying the radiated heat of type 2 & 3 civilizations (as discussed here). Some of these strategies are discussed in detail by Seth Shostak, who is a Senior Astronomer at the SETI Institute. For more similar talks visit the Google Tech YouTube channel.