When you are saving, constancy is everything. The same goes for investing - you need be constant when it comes to converting part of your savings into investments. If your investment goal is long- or medium-term, a good way to achieve it is to set a fixed monthly amount, for example, and not get discouraged. Little by little, you could get more from your money.
Remember, the value of investment funds can fall as well as rise, and you may get back less than you invest.