Our government is part of our society. You won’t like everything it does, but if you try to radically change it, you’re going to run into major difficulties.
You can wish for some changes, but there’s not too much most people can do as individuals to make a big difference. What you can do is join up with folks who are like-minded or have similar interests to yours, and work on influencing that group while helping that group influence our politics. Sometimes your group will swing an election to someone who will run things more to your liking.
The most powerful political groups are the major parties, so you might want to gauge which of the two parties suits you better and support it. Or, if you are part of a smaller movement, help your group figure out which party to back, and then support the party that your group supports.
These aren’t very original thoughts or profound insights. A lot of people don’t subscribe to them, though. Witness your average political blog commenter. They expect to get everything their own way by ranting, and if neither party closely matches their individual views, they are inclined to embrace radicalism. Radicalism’s not for me; I have too much to lose.