Below you will find a good list of resources to help you with various aspects of effective environmentalism:
If you have something you need to get rid of, and aren't sure how to go about it, in the Twin Cities the Rethink Recycling website is probably the best place to start! It will also help direct you to your local recources, like the A-to-Z "What to Do" lists in the City of Minneapolis and in Hennepin County. Where available, use your most local resources, though: for example, Rethink Recycling will send you to a store with your dead rechargeable batteries, but in Minneapolis, trash collection will recycle them for you if you set them out right - so be sure to follow the link for your county at the bottom of each Rethink Recycling page. (In most communities, alkaline batteries are non-hazardous waste, and can go in the trash. But Minneapolis, Rochester, and other communities incinerate most of their trash, and in an incinerator dead batteries become little bombs that blow holes into the side of the incinerator - so those communities have you separate your dead "non-hazardous" batteries from the rest of your trash.)
If you have something that's still good, but you don't want, or something that's broken but in good shape and you think someone else might be able to fix - don't throw it away, "Freecycle" it! Give it to someone else. You can donate working things and clothes to groups like Goodwill, which has dropoff locations throughout the country and helps employ people in need sorting and selling the donations, training them for other, more "mainstream" work. For broken items, or if you don't want to haul the item yourself, or just want to see it go to a fellow citizen, Freecycle it. Broken but relatively new lawn mowers, appliances, etc. will generally be snapped up, as will even rather old bicycles, sports equipment, etc.
In the Twin Cities: Twin Cities Free Market
In Hennepin County: Consult the Choose to Reuse Directory
You can stop most of the unwanted printed material that comes to your home by contacting a few organizations, most usefully the following (see also the FTC's pamphlet on this subject):
Phone books: http://www.yellowpagesgoesgreen.org/
Credit Card Solicitations: http://www.optoutprescreen.com/
Direct Mail: http://www.dmachoice.org/
Avoiding food waste:
Berries - wash only the ones you are going to eat; leave the rest dry. Standing water leads to rapid spoilage, while if they are dry they can easily last a week.