Because investing in stocks is a proven method for building lasting wealth, with an annualized historical return of 10% per year, many people want to figure out a way to educate themselves so they can start putting money to work. But it can all seem so complex at first.

I'm here to tell you that it doesn't have to be difficult at all. In fact, there's an extremely simple and foolproof strategy that new investors can use to make money in the stock market in 2024 and beyond. Here's what you need to know.

Going the passive route

If there's anything investors should learn by looking at the last few years, it's that the stock market is totally unpredictable.

If, at the start of 2020, I told you that a once-in-a-lifetime pandemic was going to bring the global economy to a screeching halt, you would have likely sold your entire stock portfolio and moved it all to cash. After all, this would have seemed like the prudent thing to do at the time. But that year, the S&P 500 and the Nasdaq Composite were up 44% and 16%, respectively. This goes against what a rational observer would think.

For the average investor who accepts just how difficult it is to make accurate predictions and instead wants to adopt a safer strategy, the best course of action is to buy an index fund such as the Fidelity 500 Index Fund (FXAIX -0.28%). This tracks the performance of the S&P 500 index. Even Warren Buffett agrees that this is the best thing individual investors can do.

It's obvious why. Approximately 90% of active funds out there actually lose to the S&P 500 over a 10-year stretch. This is absolutely bonkers. There are people who still pay fees for this underperformance. Perhaps it's nice having someone provide guidance and commentary about what's happening in the markets, even though the results are clearly subpar.

This just means that the best strategy for new investors is to focus relentlessly on dollar-cost averaging (DCA) in an index fund. This will produce better returns than the vast majority of active funds out there, plus the fees are low.

And it's something that can be totally automated on a recurring basis, say monthly or quarterly. You don't even have to think about it, and you can rest assured knowing that new savings are being put to work no matter what the market environment is.

This leaves people free to focus on their daily lives while having to pay less attention to gyrating stock prices and noisy market and economic news. That is a less stressful way to live.

What about picking individual stocks?

Seeing your portfolio rise by 10% per year might not be enough for some investors, even though it can be successful over time. For example, someone who invests $100 per month for 30 years at that rate of return will eventually have a portfolio balance of $208,000. That's not too shabby. And it can result in an even higher figure if that monthly allocation increases.

However, those who are daring enough might want to take a shot at picking individual stocks. The goal would obviously be to generate market-beating returns, which can boost wealth even more given enough time.

In my opinion, the best approach for those who are totally new to investing is to start off with a passive strategy, like I described above. And then, when your knowledge grows, and if you have the time to analyze specific companies, perhaps it's a good idea to add single stocks to your portfolio while also continuing to DCA into an index fund.

During a time of heightened economic uncertainty, this appears to be the smart move in 2024 and beyond -- especially for beginners.