I think that luck is very nesessary for investors. Besides knowledge and skills, there are still many factors which you cant predict. Luck will help you get.
Luck is involve there no doubt but it is also necessary that you may have some good experience and trading skill is also too much necessary for day trading, day trading require a quick decision take having strong well power, lazy people may not be succeeded in day trading. Those people who have a decision power to take a quick decision about his trading.