What is a good investment strategy?

There are two important dimensions to a good investment strategy. The first dimension is diversification: the strategy should cover a broad spectrum of asset classes. It should have mix of stocks, bonds and fixed income assets. Within each of these asset classes, it should have further diversification. Investing into ETF of index funds would provide this diversification. There could be room for aggressive investment for a small portion of the portfolio. The second dimension to the strategy is time based  periodic investment: this allows you to dollar cost average your investments. You buy less when asset values rise, and buy more when they fall.