I have found as an amateur that two of the biggest mistakes people make are trading with emotion and being greedy.
I consider the entirety of market knowledge to be an ocean and all I have is a Dixie cup. But I can make money with my little Dixie cup by trading in my comfort zone without emotion and avoiding greed. I invariably leave profit on the table each trade. I analyze my exit point and get out taking my profit with it. "Let your winners run" isnt sound advice in my worldview. And I make bad trades and lose sometimes. It just happens. Analyze what you jissed or didn't predict and learn from it.
As gamers, in my opinion, we are uniquely skilled to make money in the current technical trading world we are in. Gamers can read graphs and rules lawyer. Educate yourself on how to let today's trading tools show you lines of support and resistance. Pick maybe a dozen or so stocks max that have sound financials and balance sheets. Find out their support and resistance levels (and what that means) and make trade decisions based off it that info. Don't overwhelm yourself trying to look at all the stocks. Follow your picks. You may go a week or two with no opportunities. Be patient. Wait until the entry point or exit point is reached. And start small. No commissions makes learning with small amounts viable.