The reason many people buy into conspiracy theories is the same reason why many people find themselves attracted to religion. It's the call towards something bigger than yourself and an easy explanation as to why the world around you is the way it is. Many of these claims and groups that make the claims boarder on the edge that many religious institutes tend to find themselves in. While the notion of a conspiracy taking place can happen and has happened before (the plot to kill Caesar or the Ides of March), most of the time when someone states a conspiracy is in action most of the time once it get's tested it tends to fall apart. For this reason it is important to not only be skeptical of people in power but also of the motives of the people who are also crying out against said authority. The enemy of my enemy is not always my friend.
Extraordinary Claims
Conspiracy theories make very extraordinary claims. Sometimes these claims might not be as complex as the cliche image of a conspiracy theory most of the time it is someone who is making connections where connections shouldn't be made. When ever a claim is made it is important that it have evidence to back it up. Rumors or ideas based in false hood can have dangerous real world repercussions that for better or worse tend to manifest themselves in ways that most would rather not have happen.One of the more popular theories out there is that the government is controlled by a shadow government. This basic theory manifests it's self in various forms depending on who happens to be discussing it at said time.
The shadow government theory is the perfect example of how faulty most of these theories tend to be. Most of the evidence that is presented tends to be nothing more that the normal, well I know a guy who knows a guy, or the I saw it with my own eyes. These claims as evidence don't prove very much. The way the human operates makes relaying on this kind of evidence inconclusive. Ten people can all see the same event and still tell a different story about the same event. Memory is a very strange thing that we are still working on figuring out. With the boom of technology and the willingness of people to share classified information, why than has the only proof that has presented is first person accounts? Edward Snowdan was entrusted into one of the most well guarded parts of the US government and managed to look countless classified documents. Why than, with the shadow government theory stating it goes back centuries, has there not been real evidence that shows there is such a group been found yet? Theories may say it's been covered up, but with the bask human interaction with people who compete for power, does it really make sense that no rivalry would ever arise? Especially when it comes to who gets to control the world?
Social Groups
When it comes to conspiracy theories one of the major factors that tends to go into who believes what theory is the social group that you belong to. For example if you tend to lean more on the conservative side of the spectrum the likely hood increases that you very well may believe the birther side, on the flip the more left you lean the probability increases that you are going to think that 9/11 was an inside job. For some people they will just believe everything that they are told with asking any real questions about the information that they are presented with.
One unique trend that can be seen with the world of conspiracy theories is the increasing levels of Americans that buy into most of these if not all of them that are placed on the table. When polls are done to see who believes and who doesn't, like most things that need faith, Americans have higher numbers than most other countries. Part of this could come from a distrust of authority that resulted from the revolution from Great Britain, but more than likely it has more to do the religious aspect of the United States. When you look at the alternative networks that push stories like this most of them tend to have an undertone of right wing religious beliefs that are hidden behind the language used by pseudo-skeptics.
Debunking Theories
With most conspiracy theories applying common sense to the vast majority of them should be enough to disprove most of them. A lot of the times when theorist put out their ideas they tend to be half baked at best. The level of research tends to be limited or in some cases, comes from sources that are questionable at best. For example, the common theory of a species of space reptiles ruling the globe can be disproved easily by two things, one the probability and two basic evolution. There is a logical reason why we don't see lizards the same size as humans every, and with the ones that are close to our size or a little bigger there are limitations to their design non of which make them a sentient species. While conspiracy theories make good stories, there is really nothing more to them than that. When a real conspiracy happens they tend to not stay covered up for very long and are never as gripping as these theorists would have us think.