Traders need to be patient. There are a number of points traders need to follow in order to have any profits from the trades. All the 4 points mentioned over the source you mentioned are true and they need to be followed but any trader can't just start trading considering those 4 points. traders need to experience few things on their own and they also do need to have some loss in order to gain knowledge about what trading actually is.

Trading has huge profits and it is what makes a lot of peoples make mistakes like overtrading, etc which each time lands them into loss. Human nature has a greedy base and no matter how intelligent we become, we always have that greed somewhere in our minds making us cause some of those mistakes.