Fail fast and then fail better
Failure is only the opportunity to begin again, this time more intelligently. - Henry Ford
A lot of us are afraid of failure. For example, in business meetings colleagues avoid to express important ideas to avoid the embarrassment of being wrong.
The ironic thing is that a definition of the word expert I really appreciate is: "an expert is a person who has made all the mistakes that can be made in a very narrow field".
This basically means that if you do not speak during that meeting you are missing out an important step to become an expert in the field (not considering the fact that you may be right and so your important point of view will make people waste their time).
Do not avoid mistakes, and strive for excellence. The idea is that you will always fail, no matter what you are up to. Even if you performed the same task for years, you will be surprised by how unexpected can the world be. Your aim must absolutely not be to avoid errors, you have to fail better than others though! Make your errors excellent.
What this means is that you want to grow yourself to the point that you are more likely to fail while striving for something that has high stakes. It is less impressive if your train does not start its trip for some malfunction or if a space shuttle does not do it. You want to grow into attempting novel and untried things and be proud even of your failure.
At some point you will become so comfortable with failure that you may want to fail purposefully to get bigger insights. At some point you will be so good in your field that you may not know how to improve further. Here the trick: fail. Try new things, see them fail, and try to patch the failure somehow. This process will let you come up with at something completely novel, improve your expertise and create a new field of knowledge if you are lucky enough.
This approach is really the scientific method: for any problem, just propose a solution. If that does not work, find why it does not and patch it. If you repeat enough time, you will have a very reliable working solution. At the end of the day, as George Polya said: "If you can't solve a problem, then there is an easier problem you can't solve: find it".
So this is the path to your expertise: fail, fix it, and fail better.
And please chill out, everybody else before you has followed the same steps.