how to make a rich portfolio in stock market ?

Building wealth: 9 strategies for growing your portfolio
Pick an investment strategy that suits your goals. ...
Set clear investment goals. ...
Consider investing over the long-term. ...
Market timing. ...
Diversification. ...
Invest in growth sectors. ...
Take advantage of compound interest. ...
Rebalance your investment portfolio

So, 90/10, with 90% in the Vanguard 500 Index Fund and 10% in short-term government bonds, is his recommendation for his wife's trust. By the way, his wife is in her late 70s, and Warren will presumably be leaving her many millions of dollars