High returns can be achieved only through higher risk-taking ( and perhaps through acceptance of lesser degrees of liquidity).
The amount of risk you can tolerate is partly determined by your sleeping point.
You should understand the risks and rewards of stock and bond investing and be able to determine the kinds of return you should expect from different financial instruments.
But the risk you can assume is also significantly influenced by your age and by the sources and dependability of your noninvestment income.
You should have a clear notion of how to decide what portion of your capital should be placed in common stocks, bonds, real estate and short-term investments.
You should develop a sound philosophy and specific stock market strategies that will enable you as amateur investors to achieve results as good as or better than those of the most sophisticated professionals.
A fitness manual for random walkers