As far as changes/modification to the government:
Corruption / Lobbying (you can't separate the two, and you at the very least need to completely modify the rules of lobbying). Important in this would be to make the tax code more fair, get rid of oil subsidies, get rid of corn and ethanol subsidies, attack tax dodgers, address certain states hosting corporations in their states purely for their low / non-existent tax codes, and doing business out of state, make capital gains the same as any other tax, and lowering the the "actual" rates people face.
Illegalize high-frequency trading and basically all computer-driven algorithmic methods of using the market for money - the stock market is for investing in companies, not using computer's to try and gain money.
Complete firing and rehiring of all national workers, regulators, etc. I don't trust anyone who's in the system, and it may take us a few years to get back on track, but we need to clear house. The foundation is somewhat solid, but everything above it is so rotten it needs to go.
Publicly finance elections. It's worth the cost.
Modify the rules of congress / senate / executive to adopt a parliamentary system. We need major reform to our system, and I think the idea of electing a President separate from the House and the people is undesirable. What you get under our system is a President who can't do shit because Congress doesn't listen to him - that's impossible in a parliamentary system, becuase the PM will face a vote of no confidence, and be replaced by the a national election (or at least how it could work).
Severely reduce our foreign empire; end the wars basically immediately, and pull out contractors or nearly all contractors.
Invest in solar panels and other green technology for governmental buildings and infrastructure, one time stimulus of solar and greener infrastructure, including small scale nuclear.
Major change in food subsidies to encourage small and individual farmers and growers, and stop giving beneficial treatment to certain crops.
End of the drug war, and non-criminalization of all drug use. We make our border problem in Mexico a much bigger problem due to our insane laws.
Universal Health Care; there are a variety of ways of going about it, but basically extreme profit and health-care don't create a very good system. Other countries do it better, and cheaper as compared to GDP, than us, and get better results. Single-payer akin to Medicare is probably the best route, insure everyone through taxation and bypass that individual mandate legality issue. Al though a system like Germany would probably sell better in this country, because it gives individuals the option of still paying more for health care.
Like health care, education needs to be single-payer. Allow parents to send their children to the school they want, setting a specific amount a year you will pay for schooling, and parents and families can pay beyond that.
Individually:
Promote the local market, support local craftsman, support local farmers, join a local credit union, and try and grow some of your own food. This would dilute the money flow to some big corporations, as well as being more sustainable. This would communalize the flow of money much more than it does now, meaning the 1% wouldn't get off so well.
I think that generally sums up my thoughts on the matter. Possibly a few more issues I could think of.