From lecture 194, MEDITATION: ITS LAWS AND VARIOUS APPROACHES — A SUMMARY (MEDITATION AS POSITIVE LIFE CREATION):

The third stage is visualization. Let us first understand clearly what visualizing is not. It does not mean wishful thinking, daydreaming, fantasizing, illusory hope. All of these are attempts to whisk away hopelessness, which, in turn, exists because of destructive attitudes and traits one does not wish to face and give up, or residual feelings one does not wish to experience.

Visualization means perceiving yourself in the state you wish to attain, experience, become: feeling yourself in that state. You can experience yourself in meditation as loving, as opposed to resentful; fulfilled, as opposed to eternally wanting and empty; joyful and content, as opposed to anxious and depressed; or whatever else you are concerned with. Visualization follows proper conceiving. Conceiving means considering the desired state or experience as a possibility, visualization means feeling yourself in that state. It does not mean picturing particulars, for that may easily lead to wishful daydreaming, which is more a hindrance than a help.

If you find yourself incapable of visualizing the desired state of mind, feeling, or experience, that is an immediate sign that you are unconsciously blocking yourself, using a “countertruth” and therefore maintaining a hardened, unimpressionable soul substance, and/or weak thought-power. You should then work on that. The process of visualization requires a constant tuning in to awareness of your inner responses.