Imagine something wonderful. It could be anything, as long as it's a fantasy spun out of your imagination. Concentrate on making what you imagine as real as possible. Think of sensations, shapes, textures, temperatures, the person or persons you're with, the feeling you get when you place yourself in this fantasy.
The fantasy could be personal, professional, or global. Do you wish for peace on earth, that everyone had a decent home and enough to eat? Imagine how you will feel if that were to materialize, how differently people would behave, what their priorities would be.
Do you long for a job change? Imagine asking your boss for some of her time; tell her you'd like to share some thoughts you have about your work. Then see yourself going in, sitting down, going over all that you've accomplished over the year, and asking to be promoted, with a new title and office. Then imagine your boss, with a huge smile on her face, agreeing with you wholeheartedly, telling you it's a pleasure to reward such a productive employee, that she wishes all her employees were equally effective.
Keep this or any other scene in mind constantly, and return to it whenever you have a moment or two to think about whatever it is you want. Elaborate on your vision. See it as already having happened.
— Alan Epstein in How to Be Happier Day by Day