Essentially, our daughter is much more likely to partake in an activity (be it eating her veggies or anything else) if she feels like it was her idea to do so.

Essentially, our daughter is much more likely to partake in an activity (be it eating her veggies or anything else) if she feels like it was her idea to do so. I'm not entirely sure if it's the choice aspect, or the preparation aspect (in other words, that she knows in advance what to expect). We're careful to emphasize the sanctity of personal choice wherever we can, and to encourage her to make her own decisions based on an evaluation of her options (really, we're fine with her picking any of the menu options we give her; if she picks a gross combination it's hers to eat, not ours). The important thing seems to be that once she makes a decision, she becomes invested in it and is much more likely to see it through. I probably shouldn't discount the preparation aspect, however. She eats much more of her lunch when she helps to prepare it (and thus knows what to expect when she opens it at school). Similarly, we have a countdown for bed ('bedtime in t-5 minutes! Bedtime in t-2 minutes!') that makes the transition to nighttime more or less painless.