If you're very risk averse, can consider parking your money in CPF or in high quality bonds. Bonds are generally considered as safer than stocks (but not entirely risk free!). Tradeoff is that returns are also correspondingly lower.

If you are OK with moderate risk taking and have a long investment horizon (10years and up), suggest you can explore Dollar Cost Averaging (DCA) into low cost index funds. Simple, fuss-free and doesn't require much effort in monitoring.

At the end of the day, your returns are proportional to the amount of risk you are willing to take.