Build yourself a trading plan that will guide you in the market, and this is actually the most effective way to actively remove the loss transactions due to emotion.

That's true because most are the problem in trading is not only a losses but also the emotions. If we want really want to trade we need a plan to how we can manage well our assets and also how to hold our emotions.
Trading plan is just a plan, your emotion is separate because that's how you manage yourself in trading.
That plan will only be useful if you can effectively do it, provided you have a working plan, if you are not good in managing your emotion, that plan would be useless.
I think it's the other way around. Having a solid plan can help reduce the influence of your emotions since there's something you can follow. Regardless of what the market movement is, if you have a plan and is resolved to follow it, it's easy to make rational decisions.