I think I got lucky, but I think luck is required to be successful at anything (including coding). I actually haven't had any bad luck yet, the only stocks I've lost money on so far have been some of my value stocks. I fully expect some of my risky investments to go south.
The best advice I can give is pretty generic - follow the data. First of all actually find the data. Don't trust some finance news rag to tell you anything meaningful, some of them actually have a direct incentive to lie to you. Now that you have the data, what does it say? This sounds simple, but everyone told me I was an idiot to invest in GME in January. They said the same thing in March. So far my investment in GME has more than a 10x ROI. I'm just using GME as an example because it's topical - people tell me I'm in a cult while I'm actively making money betting against them.
"Buy the rumor, sell the news" is pretty easy to understand, just find a stock you know well (I would guess something in tech, like Alphabet or Amazon but whatever) and look at dates for stock movements, rumors, and announcements. You can do this retroactively to find a pattern then try to apply it moving forward. "Never invest in something you don't understand" is general advice outside of stocks, but just an extension of what I said initially - do your own research until it makes sense to you.
I think a huge amount of inertia is just people afraid to try it because they've been conditioned their entire lives to believe they can't make money doing it. I'm quickly realizing how much of this is bullshit (I realize I'm lucky and I understand I'm likely in a local maxima, but I am still extremely confident a lot of the things I've been told are just wrong). So take a small amount of money and invest it and see how it goes. Learn. Iterate. Improve. The goal is to start making money before you lose it. I actually started with just $10k and once I started to figure it out put in more money as I wanted to increase my profit.
At the end of the day it's your money and you should do what you want with it. So long as you understand you will definitely lose money sometimes and are willing to learn from it, give it a go with whatever money you're willing to lose.