Affirmations work just like Hypnotic Suggestions in hypnosis exercises. Say them enough and you eventually believe them literally. While visualizing, repeat some affirmations. This naturally gets more of your senses in tune with the process thus making the experience more real, and that's what you want. You want it to feel real.
Do this regularly for about 5 minutes or so right before meditation.
This really really works! Your belief in the process has a direct effect on the results you get. The more you know about meditation and visualization, the more you're programmed to believe in it. Belief in it, is trust in it. Within the Laws of Manifesting and Attraction, the Power of trust should be your best friend. Keep close sight of that.