I was reading The 4-Hour Body by Tim Ferriss and found two quotes that are highly applicable to trading:

On psychology:

Does that mean [the workout routine] won’t work for some people? No, it just means that it will fail for most people. We want to avoid all methods with a high failure rate, even if you believe you are in the diligent minority. In the beginning everyone who starts a program believes they’re in this minority.
Take adherence seriously: will you actually stick with this change until you hit your goal?
If not, find another method, even it it’s less effective and less efficient.

On listening to others:

Everyone you meet (every male, at least) will have a strong opinion about how you should train and eat. for the next two to four weeks, cultivate selective ignorance and refuse to have bike-shed discussions with others. Friends, foes, colleagues, and well-intentioned folks of all stripes will offer distracting and counterproductive additions and alternatives.

Nod, thank them kindly, and step away to do what you’ve planned. Nothing more and nothing different.