What's your super power?
OK, it's almost too easy at this point. Combine asking someone's opinion and demonstrating that the person has had impact on your life and you've provided him with two of the most gratifying, basic experiences of the human condition. It doesn't matter really whether you tried a new restaurant on the other person's advice, followed his suggestion on how to begin an important conversation, or started getting up 15 minutes earlier for a week because he said it was a good idea. Simply being listened to and having impact makes people feel better. Bonus points if his suggestion created a positive result, but you'll get credit regardless. [Related: "You were right."]
People have self-doubts. You do, I do, we all do. (Heck, every time I write a column here--and this is number 167, by the way--I wonder how people will react.) When others simply say they believe in you, however, it becomes easier to believe in yourself. Here's an analogy. Have you ever gotten into lifting weights, or simply watched people do it? It's amazing how the slightest bit of assistance from a spotter--with force equal to the weight of a pencil--can help someone lift far more weight than he could on his own. It's the same concept here--just that small expression of confidence can push people to achieve more--and then to be thankful for the help.