don't have a magical fix. My latest pet theory is that, at a Federal level, there should be a specified number of politicians. Rather than state-by-state, gerrymandered-district-by-gerrymandered-district, shit should be direct. Is there 3% of the US population who are pot-smoking tree-humping eco-dweebs? Then 3% of the politicians should be from the Nature Molestin' Party. Sure, we wouldn't have the 'hope and change' of meaningless party swaps over individual seats. We might get locked into some terrible shit if the majority of the country are, in fact, clueless assholes. But it'd be better representation.
A much "simpler" change (in terms of concept, not ease of execution) would be to go re-learn the concept of Federalism and take a bunch of power away from the Federal government and give it to state and local ones. The less the Federal government has responsibility over, the less harm unaccountable Congresscritters can do.