The concept of democracy is a great idea, but recent trends have shown that it is a vulnerable one, too. It seems that all a leader has to do is cut the education and social security budgets and create a large mass of people that are poor and illiterate. Spend all the money you didn't spend for the sake of the people to finance a huge propaganda campaign instead, and once you have brainwashed the gullible 51% with your "new world" views, it doesn't matter at all what the other 49% say.
Here's the fix: I propose to put several other questions on the ballots as well, questions that should be fairly easy to answer for the average adult - a mathematical one, a geographical one, an economical one, and so on. The last question on the list should be the one for the President/Party/Prime Minister you want empowered, but your vote should only count if you got the previous questions correct.
With the new system, we can even do away with age restrictions. If you're 14 and educated enough to understand the world we live in, go and vote! If you're 90 and have trouble remembering your own name, chances are your vote won't count. This may sound tough, but remember that voting is an extremely important process, and you should definitely possess a sound mind on election day. So why not prove it?
See your vote as a weapon. Careless voting can kill. Protect a gun from abuse by storing it in a safe place, and protect your vote by safeguarding it with a minimum amount of education. Doing so is your own responsibility as a voter. Basically, if someone wants to manipulate you to get your vote, I'd say that's fine. But to do that, they'd first have to spend money on your education so you can pass that test. That in return makes it harder to brainwash you. If they still manage to do it, good for them - now you at least got something in return!