If you want to become a better caster you have to be willing to critique yourself as you practice. Honest self-critique is a useful part of the process toward personally adjusting both mind-set and physical skills. Of course, one can also overdo it.
I’ve seen casters who were so critical of themselves that they could not advance in their abilities without waging a deprecating mental battle. I’ve even seen casters who were so distracted by internal fury that they just stagnated, no matter what the encouragement. Don’t take that path!
If you are willing to look truthfully at your skills (perhaps the hardest part?), but do so with the attitude of making positive change, then you’ll be on a better road. But—and I have to emphasize this—wanting to become a better caster and actually devoting a mind-set to doing it, are two different things.
For a critique to be truly effective, there must also be action, and that means physically changing what you are doing.
This requires a second level of critique, one where you have to make your body obey. For example, if you know that you need to adjust your arm movement on your backcast, but you don’t force your body to make the change, then change will be very hard, indeed. Taking critique from thought to action means that you have to create change, not just hope for it.
No matter whose books you read, no matter whose videos you watch, and no matter whose fly-fishing schools you attend, the only person who will ultimately make you a better caster is … you.