Visualisation is the process of actively creating an image in your mind of the person you wish to be and holding that image over a period of time. By shaping this mental image repeatedly in a relaxed and receptive state you may change the derogatory nature of the commentary of your inner voice and become, at the very least, closer to the person you wish to be.
Be specific. Include as many details in your visualisation as you can. Don't create obstacles by visualising the steps needed to reach your goal. Imagine being that person and how it would feel, now.
Repeat your visualisation as often as possible every day.
Become your visualisation.