Under most "democratic" processes at various levels, there are always two ways to make your influence felt. Voting is the most accessible; everybody, no matter how poor, busy, stupid, etc. gets a vote. The less obvious way is to run for office yourself.

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Anyone who seriously believes that the political environment in their (democratic) country is screwed who does not attempt to run for office (or otherwise becomes politically active) is deliberately washing their hands of the matter and should no longer feel entitled to complain.

Like a party, don't like the candidates? Join. Become involved in selecting the candidates. Pick someone out you do like, encourage them to run, then campaign for them.

Don't like the current parties? Start a new one. Rally like-minded people around yourself. If the situation is really so endemic as you believe, you won't have problems finding supporters.

"If you're not part of the solution, you're part of the problem". The most common cause for political corruption is voter apathy; given the choice of two crooks, they vote one of them in, instead of rejecting both and finding an honest person to run instead.
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To anyone who has feelings similar to the above author I would recommend ''Take Back Your Government! : A Practical Handbook for the Private Citizen Who Wants Democracy to Work'' by RobertHeinlein. (Listed as out of print at Amazon -- ASIN: 0671721577). While some of the methods are outdated, the political ones in this book are as old as politics and would serve you well should you endeavor to RunForOffice.