Try the Lesser of Two Evils
What to do: Replace the bad habit with a good one—or at least one that's more benign.
Why it works: It's much easier to slightly change a mental pattern than to reconstruct it entirely, says Jeremy Dean, PhD, psychologist and the author of Making Habits, Breaking Habits. Since you've already trained your brain to respond a certain way in a certain situation (wake up, drink coffee), you can "trick" it by directing it to respond to the same situation—with a slightly different activity (wake up, drink green tea).
What habit it helps break: Substitution can probably help you quit Candy Crush—for good, says Jamie Madigan, PhD, a psychologist who writes about the overlap between psychology and video games. There are many reasons why this game is uniquely addictive: mandatory time-outs that make you long to keep playing, one-handed controls that let you play anywhere, notifications that nudge you to sign in and the ability to compete against Facebook friends. But all of these tricks wouldn't matter as much if Candy Crush didn't have so many levels—upwards of 500, at last count. You start playing while waiting to check out at the supermarket and keep playing after you get home, on and off for the rest of the night. Instead, find something else to help you pass the time in line—ideally, a productive habit like logging your exercise on your phone. At the very least, Madigan suggests switching from Candy Crush to a more traditional game that is easier to beat (so, not Angry Birds) or a game that requires real-time interaction from a friend, who can alert you when it's time to stop playing and say, "Go to sleep!"
Make a New Mantra
What to do: Start by asking yourself, "Why do I do this, anyway?" Sure, because you're bored, but what else is happening? Where are you? Who are you with? What do you see, smell or hear? That's your trigger, and let's call it X. The next time X happens (because it will—you cannot rid the world of coworkers bearing baked goods, for example), you need to be ready. You need to have a plan to combat it. That's your Y. Repeatedly remind yourself: "If X happens, I will do Y."
Why it works: You're reminding yourself of your resolution—out loud, and often. Research on both humans and animals suggests that even after bad habits seem to have disappeared, they still lie dormant, waiting to be reactivated, says Dean. If you have a plan for how to deal with that situation, you won't be taken by surprise and default to your old frenemy, the bad habit. (Note: Recent analyses of this strikingly effective technique have shown that it backfires if you say, "If X, happens, I will not do Y." E.g., "If I get hungry while watching TV, I will not have ice cream...or chips...or peanut butter out of the jar.")
What habit it helps break: Snacking ("If I want something to eat while watching TV, I will have a cup of yogurt"), squeezing pimples ("If I notice a red spot, I will dab cover-up on it"), cursing ("If I spill this really full mug of coffee, I will say, 'Flippers!'").
Next: How your calendar can help