Words.

Never underestimate or overestimate the power of your words. Choose your words wisely and carefully. They are a direct representation of your inner being. Observe how your words affect others around you. Be mindful. You will start to learn who you are. Precisely. Don't allow yourself to "slip up." Say what you mean and mean what you say. Simplicity is best. And when you have to say something that is not so nice, debate  with yourself if it is worth saying. You will most likely find that you will choose the latter; not saying anything at all. You won't be displeased with your decision. :D