I think the best advice she gives (or relays from someone else) is to not try to change your food buying habits all at once. This is the approach I've been taking. I'm not a vegetarian, but my girlfriend is (for ethical reasons), and this sometimes causes us some...discomfort. I'd try vegetarianism if I could, but I have a strong distaste for so many vegetables, the culinary options available to me if I cut meat out of my diet would be very few indeed. Maybe that's no excuse.
But I try to make concessions. One of them is to only buy grass fed beef, for example, which not only benefits my health (no chance of mad cow disease), but also -- as Hassinger points out -- is better for the environment. I also try to buy organic products when I can, but sometimes they're just too expensive.
My attempts at growing a garden have failed so far.
Having grown up not having to think about where my food was coming from, it's difficult to transition into seeing diet as an ethical decision. Used to be the issue was, "There are starving children in Africa, so appreciate what you have and eat it." Hassinger presents some options I hadn't considered, such as buying directly from local farmers. Giving people the knowledge not just of what's wrong but also how to fix it is important, and I'd be interested in hearing more ideas.