Whenever you have a self-conversation, you are always talking to yourself in the present moment. And in each present moment, you get to choose what you think, what you say, and what you do.
You can express it this way: "I am always in the here and now, and in the here and now, I create my present experience with the thoughts that I choose to think."
This idea is tremendously empowering. This idea can enable you to free yourself from much of the distress that you might unnecessarily cause yourself. Everything you actually experience is your present experience, and your present experience is based on the thoughts that you think right now.
To master any positive quality, you must master being able to access or create that positive quality in the present moment. Let's say that you would like to master the ability to be happy and joyful whenever you wish. You only need to be able to access or create happiness and joy right now. As you do this, you will realize, "I am always in the now. Because I can be happy or joyful now, I can choose to experience this whenever I wish."
The same applies to many attributes: you only need to access them now, not in the future. You only need to choose kindness and compassion in the present moment. You only need to choose patience and serenity in the present moment.
You only need to access your courage in the present moment. Some moments will be easier than others. But as long as you have courage stored in your brain (which is always with you), any time you think that it would be great to have courage now, you'll have all you need to have courage now. This way of looking at courage makes it much easier. You don't need to think about maintaining courage later on. You only need it now. And whenever you want to experience courage, you will be in the "now."
Whenever you think about the past, you aren't in the past anymore. You are in the present thinking about the past.
Whenever you think about the future, you aren't in the future yet. You are in the present thinking about the future.
People who have mastered the ability to realize that their thoughts are always in the present free themselves from much worry. All worry is about the future. The future is unknown right now. You can pray for the future. And it is wise to plan for the future. But since you are always in the present, it's not a sensible thing to cause yourself needless distress or suffering for what might or might not be later on. It is better to utilize your time in the wisest way for now.
(from Rabbi Zelig Pliskin's book: "Conversations With Yourself", PP.30-1) [Artscroll.com])