How do I keep from snacking when bored?

Physical activity. Wow, many people have this problem. Try to sever the connection with being bored and eating. Find a better substitute, preferably something involving physical activity. Take a walk outside or on a treadmill, go to a park, shoot some hoops. If that fails, read a book or even turn on the television.
Snacker. Snacking is more common for women than men in my experience. Boredom is only one of the reasons we snack. Sometimes we don't balance the nutrients in our meals. Protein, fiber, and some fat can make us feel more full after eating a meal, so we naturally won't snack as much. A way to get a handle on snacking is to do a food journal. By wriiting down when, what, and where we eat; we often eat less.
Activity, selectivit. Don't just sit there, do something, preferably active. Don't skip meals, have protein at each meal. Be selective about what you snack on-go for foods that are high in water, fiber, low in calories-like fruit, veggies. Don't keep "problem" foods in the home. Out of sight, out of mind- some people have to avoid entire aisles in the supermarket to avoid cues to get certain foods. Exercise ur mind2.