If you would like to increase the interest received on your money, then holding a portfolio of value stocks or an index ETF will outperform your bank account by a large margin over time. This takes very little effort, but will suffer from the occasional (large) drawdown that you have to sit out or this strategy won't work.

If your primary objective is capital conservation then buying high quality debt of countries would be a good idea. Singapore or Switzerland are good candidates if you consider it a real possibility that the US could default on its obligations. Otherwise you could hold Treasury bills and roll them over once they mature or you could use an ETF like SHY that holds short-term Treasury bonds.

You could also buy precious metals if you are convinced that civilisation is going to end in the foreseeable future. Drawbacks are fluctuating prices and the complete lack of interest payments.