If you're a picks and shovels investor, buy GPU chipmakers like Nvidia, AMD, and data centers. If more interested in customer side offerings, buy Alphabet, Microsoft, Salesforce and others with access to large databases, cos that's what GPT/AI needs.

It's hard to boast of much success in the current situation, but what worked for me is:
1. Always read as much as you can. Read broadly, read deeply, and associate what you read into current affairs, the companies or sectors you plan to invest in, the people they serve or sell to.
2. Decide on a plan/strategy to invest and stick to it. eg hold x% cash in good times and invest y% when markets dip, take profit at 20%, whatever.

A mindset is something your brain settles into, perhaps a thinking habit or a cognitive reflex action. We know how difficult it is to change these: with a habit, get rid of "h" and you still have "a bit"; get rid of "a" and there's still that "bit"; get rid of "b" and you still have "it".
So how do you *improve* your mindset? Others have pointed out "fear" and "greed" as the inescapable 2 sentiments as an investor. There's no way to avoid feeling these, unless you...