Our (US) system of representatives could be modified so that there would be many more representatives, whose purpose was shifted to being the conduit of the demands of the majority of their constituents (basically just order-takers as opposed to people who could operate fairly separated from their constituents, once elected).  These representatives would essentially represent the desires of the people.  With the internet, we finally have available the technology for people to register what their desires are.  It would be here that the tyranny of the masses would be evident because the majority of all people's desires would control the outcome of the actions of the representatives.  The legislation would have to be kept to narrow focus so that the desires would be accurately reflected from issue to issue, and special interests would be obvious.

So whence the check against the tyranny of the masses? Statesmen would be appointed to be Senators, with long terms with high salaries. Thus they would be  less likely to become prey to small interests, and would not be beholden to a voting constituency except in egregious circumstances. Using the major fields of study at universities as the areas in which to review people, the Statesmen would be appointed from the best of those actually practicing in each of the fields as an unsolicited honor and obligation.  These Senators would essentially serve as the public conscience, along with the judicial system, which is entrusted with carrying out the intent of the law without bias.

One other check would be providing media access to minority views.  The media are the primary, if not sole, source of most people's information.  If the media are biased and do not give an opportunity to minorities to express their stand on issues, the media are effectively controlling the knowledge base upon which people will be making their decisions.  This by itself will not be enough because shows provided as entertainment can also influence what people think and feel.