This came to me about 5 years ago, but it changed my life at the time and I didn't think to share it with others until recently.
Impoverished people think in terms of lack: why am I so poor? Why don't I have a better life? Etc
Successful people naturally think in terms of substance and abundance though...
Why do I always have more than enough?
Why do make more than enough to take care of my bills?
Why am I living in complete abundance?
Why am I completely satisfied and fulfilled?
Why am I so happy and energized everyday?
I think you get the idea.
Some personal development products have been made around this idea, but it's so simple I think it's ridiculous not to share something so basic.
When I first did this I recorded my voice and played it for about 10 - 30 minutes per day to reprogram myself over about 15 - 20 days.
It helped immediately and my life shifted in a very unexpected way.
It's literally just a series of positive questions.
Make about 5 - 10 basic questions about things that discomfort you / make you uneasy that point you toward your goals.
We are not aiming at mediocrity here; only abundance and being the best that we possibly can.