Everyone is different, and every situation is special. So, what might work for one person might not work the same for another, and it might not work all the time either. Here are some tips to help you set aside your emotions and stay focus on your trading strategy.
As a human being with interest in learning how to trade or already a trader, one thing you have to master before you become successful at trading is controlling your emotions because when you're not able to control your emotions you can't stick to your trading plans and that would become an issue when you want to trade. All the tips you mentioned are good but they can't just be executed without been able to control your emotions first. Making plans and following it up without breaking then can only be possible when your emotions are already under your control and so is only investing in what you do understand because when you don't have your emotions under control you'll be easily be distracted with trends in the market
Investing with money you that you can afford to let go will help you with your emotion management because one reason why traders aren't at peace with the market is because they invested so much capital into the market that it begins to worry them but when the capital invested is in the category of spare money, you won't be bothered much about the market. Another important thing to always do as a trader is to take break, it doesn't matter if you're winning or losing but always take breaks as it gives your brain rest and time to think which will be helpful for future decision that you'll have to take when you're resuming your trading.