Let tax payers to allocate, say 1% of their taxes as they want. This would not be enough to prevent our representatives from doing the business of the government, but would show, on a yearly basis how the people think their money should be spent.
In addition, I would like the results, with proper statistical categorization to be available so that we could see which groups, areas, etc. wanted to send the money in different ways.
If it worked out, then perhaps the percentage could be increased and the option, to reduce the amount money to the government could be added by permitting people to allocate some money to a charity.