It is true that one manifests the reality that appears in one's consciousness. The reason why one appears to have such limited conscious control of that reality is because that which is identified as "self" is limited to one's conscious mind, which is actually a mere shadow of the totality of what any given individual is. Most people have the illusion that their behavior is essentially under the control of their conscious mind, but in point of fact, most human behavior has been shown to originate from subconscious motivations.

It seems self evident that we are aware of who we are, and yet most of the time we are only aware of the conscious portion of our mind.

Consideration of the phenomena of lucid dreaming can be most revealing about our concepts of self. A popular misconception is that if you are aware you are dreaming you can control the dream. The misconception stems from the confusion between who is the "real you", the dreamer or the "dreamed you". When you become aware you are dreaming, your identity shifts from the "dreamed you" to the dreamer. The dreamer has always had control of the dream but this only becomes apparent when one becomes aware that they are dreaming.

In addition to the conscious and subconscious mind, each individual also has a "superconscious mind". This is the awareness transcending the limitations time and space that is experienced in deep meditation, trance and various other "altered states of consciousness". The degree to which an individual gains control over manifestation has much less to do with belief than it does with recognition of their subconscious, conscious and superconscious mind.