Appreciation is the best form of encouragement is what I believe. Appreciation is what that leads to a person repeating his work again and again and grow it more and more. Only through appreciation can one show his/her support towards someone in the simplest format. Every appreciation improves the confidence in the other person.
Generally we are awed by some skills or talents of others that we don't possess ourselves. Even by the success or wealth that one has achieved we are surprised and appreciate such people to an extent that we become marketers of their names. We appreciate all those stuff in others which we ourselves do not possess and there is absolutely nothing wrong in it. When we see people doing what we can do, we just think that it's not out of the box and something that everyone can do and hence deny that person of appreciation. Probably that thing which is so common to you might be the next difficult task that the other person has just achieved. Probably you have grown through the stage what the other person is reaching now. Unfortunately our mind doesn't appreciate what we already know and the other person loses his share of appreciation.
It's very important to observe and learn how people around you are developing. No matter how much ever successful you are, you still have to have an open eye to appreciate every small development in people around you. In fact the most noticeable quality in most successful people is that they appreciate the smallest of the good things that they notice in people. Feel free to share your appreciation on email@example.com