It seems to be impossible to have that combination of low risk and high returns but it has been historically shown that International portfolios will do that when compared to domestic portfolios. The best way to manage your risk is through Smart Diversification. Or what i called Intelligent Risk Taking. The way to do that is to invest your money into an international Portfolio, the trick here or the most important part is to invest in stock that are not correlated.
Wherever there is low correlation between the stocks, then there is a great chance for diversification. When u have 2 stocks are both highly correlated, then there is no reason to diversify , we just go with the stock that has the highest return. So look for stocks that have very small correlation, and in international markets, that way you hedge the currency risk and exposure, being in more than one market and one economy, and pursue higher returns because it has been historically shown that international portfolios have higher returns with lower standard deviation which means lower risk. International Portfolio also capture higher number of stocks where in domestic markets , you are only limited to a certain number.
To make it easier, use asset allocation softwares. those available software will do the allocation part for you, the software will test for correlation between the stocks you have picked and give u the optimal percentage combination between those stocks. Google " Asset allocation programs" and you will get plenty that will help you to do that task.
Remember, International Portfolio, 8 to 10 stocks, low correlation between the stocks though using an asset allocation program to determine the optimal combination between the stocks. it will only make your life easier and your investing more intelligent.