I also boycott Coors , General Electric and Domino's Pizza for their anti-choice stance and their right wing financing. But one of the most fundamental methods, and the one that strikes hardest at the obnoxious system, especially if enough people participate, is the spending or non-spending of one's funds. True, we must pay the power and phone bills, and most of us depend on petroleum products for travel, but there is some choice. I have used both Working Assets and Allnet as long distance carriers. Allnet is the only company with no ties to weapons building.
Food choices are one of the easiest places to exercise dollar power.
I go to local fruit stands or Farmers Markets for produce. I never buy commercial table grapes because the United Farmworker's Boycott is still on. I avoid Safeway because of their past anti-consumer practices and their vertical monopoly on many products. When possible, I shop at locally owned markets. The few extra pennies I pay are worth it because more of the profoit stays in the community.