To begin, I'm going to address the economy. Here are the two things you can do to help the economy, as it affects regular people (not the super-rich).
1. Try to utilize local businesses over corporations, and buy stuff made locally or domestically rather than stuff made overseas. Use farmer's markets, locally owned restaurants, mom and pop shops, or even buy stuff from people on craigslist.
2. Use a local bank or a credit union if you're not already. Avoid the major banks at all costs.
The rationale behind these suggestions is to keep money in the community. Studies have found that money spent at local businesses has a greater impact on the local economy than money spent at a corporate chain. This is because local businesses spend more money locally than major corporations. Major corporations are legally bound to be profit-driven. Because of this, corporations are by definition trying to get as much money out of the community for as little value as possible (i.e. turn a big profit). On top of that, they must keep overhead (spending) down. Where does the money go? Proportionately, far less goes back to regular people than it goes to the super-rich and to people in countries where jobs have been outsourced to. I know this is a generalization, but statistically it describes the situation accurately in a simplified form (so there are lots of details being glossed over, and some exceptions, but it works as a general rule).
As far as the bank thing, local banks and credit unions support the communities they are in, by providing loans to the people and small businesses in that community. This is made possible by the deposits of the people in the community. The major banks, the ones bailed out by the government, use deposits as a way to invest in complicated financial devices (that aren't very different than gambling), and do unethical things to make money, such as pushing bad loans to make money in fees and then reselling those loans as complicated financial devices.
These are relatively simple, but if a significant group of people begin to do them, it could help the bad economic situation that we see everyday in a real way.