Obviously there are no 100% guaranteed ways to double your money in a year, otherwise everybody would just do that instead of working for a living. I wouldn't recommend putting all your eggs in one basket, so you should invest in several areas to spread out the risk. I'd also recommend looking at investment as a long-term commitment (e.g. 3-5 years or more). I invest in the stock market, specifically dividend stocks. The most reliable stocks (e.g. Dogs of the Dow) pay 3-5%, and some of the more risky ones pay 5-12%, and up to 15-20% for REITs. For the last 2 years I have been leaning toward the REITs, since the real estate market is in recovery and should continue to improve over the next 3-5 years. With a good mix of dividend stocks you can spread out your risk and still get a healthy return of 8% or more.