I bet many people will tell you that you can’t because of diversification and other myths and misconceptions what all sorts of advisers tell general public to cover their backs and lack of deeper knowledge.
I started like that myself and built up a nice portfolio. It is difficult at first but doable, mainly today when you can trade commission free. That is a key. You must choose a broker which will allow you to buy a single share and charge you nothing for it.
The next thing is to choose a high quality dividend growth stocks (dividend aristocrats) to boost your income from your holdings, and reinvest that income. At first, use DRIP, later on I would recommend buying more stocks different than those which generated the income.
At first, choose only about 5 to 10 stocks and start buying them and accumulate.
Here is my portfolio I opened in April 2019 to do exactly what I preach. As you can see, even though the portfolio is small and generates small income, but it is growing. And given the size of the portfolio it is still sufficiently diversified as the point is not in owning hundreds and thousands of stocks but stocks which can hedge each other. So you can have only 5 stocks and achieve the exact same or even better diversification than someone who is buying hundreds of stocks.
Note, the stocks above are my holdings and not a recommendation or solicitation. If you decide to buy them, do so on your own risk and you must do your own due diligence and be aware that you may lose money.
Also, my broker charges me zero commissions so I can buy a single share and it cost me nothing. Before, when the brokers charged commissions I first had to save at least $600 dollars to buy a few shares to mitigate impact of the commissions so I was buying shares every 6 months. Today, you do not have to wait and you can start buying a few shares every month and slowly accumulate.
I have done a similar thing with my son’s ROTH. He is at Fidelity and has a basket of 4 high dividend (+6.5%) REITs with the dividends reinvested. He only had about $ 200 to begin with so we were buying 2-5 shares of each, now he is investing monthly $ 50 but receiving dividends monthly/quarterly. Last year was an anomaly and he earned 18% on the stock (not complaining of course). Start small and be diligent and it will amaze you what develops. Working on him to start to sell covered calls as soon as he accumulates 100 shares of each stock.
I did the same with my daughters. They started investing when they were 10 and 13. Now they have a bit more in their accounts, reinvesting their dividends and growing it. I keep explaining to them that even when investing a small amount of money every month for the next 30 years (and hopefully investing more as they get older) they will be able to retire in their 30s or 40s. I plan on teaching them CCs too (as soon as they accumulate enough).