The principles of investing
Goals, time horizon, risk and diversification are key elements to consider when investing.
Thinking about what you are saving for can help you decide how you invest and what you invest in, and means you are more likely to commit to regular saving.
Investing is best when you think long-term. It means your investments may be able to recover any short-term losses, as well as benefit from compound returns.
All investing has risks attached to any potential reward, but this can vary from investment to investment. You need to ensure you're happy with the risks involved with whatever you choose to invest in.
Owning different types of investments (perhaps through an investments fund) means if one doesn't perform well you could still recive the potential returns of others.