Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How to acquire skills required for long-term investing?
I feel that OP's question is fundamentally wrong and an understanding of why is important. The stock market, as a whole, in the USA has an average annualized return of 11%. That means that a monkey, throwing darts at a board, can usually turn 100K into over three million in thirty-five years. (The analog I'm drawing is a 30-year old with 100K randomly picking stocks will be a multi-millionaire at 65). So to be "good" at investing in the stock market, you need to be better than a monkey. Most people aren't. Why? What mistakes do people make and how do you avoid them? A very common mistake is to buy high, sell low. This happened before and after the 08's recession. People rushed into the market beforehand as it was reaching its peak, sold when the market bottomed out then ignored the market in years it was getting 20+% returns. A Bogle approach for this is to simply consistently put a  part of your income into the market whether it is raining or shining. Paying high fees. Going back to the monkey example, if the monkey charges you a 2% management fees, which is low by Canadian standards, the monkey will cost you one million dollars over the course of the thirty-five years. If the monkey does a pretty good job it is a worthy expenditure. But most humans, including professional stock pickers, are worst than a monkey at picking stocks. Another mistake is adjusting your plan. Many people, when the market was giving bull returns before the 08's crash happily had a large segment of their wealth in stocks. They thought they were risk tolerant. Crash happened, they moved towards bonds. Then bonds returns were comically low while stocks soared. Had they had a plan, almost any consistent plan, they'd have done better. Another genre of issues is just doing stupid things. Don't buy that penny stock. Don't trade like crazy. Don't pay 5$ commission on a 200$ stock order. Don't fail to file your taxes.  Another mistake, and this burdens a lot of people, is that your long-term investments are for long-term investing. What a novel idea. You're 401K doesn't exist for you to get a loan for a home. Many people do liquidate their long-term savings. Don't. Especially since people who do make these loans or say "I'll pay myself back later" don't.