The 'trick' to success on the market 'buy low, sell high'. Unfortunately, most people- god bless them- do exactly the reverse. Behind every opportunity there is panic (or a margin call) ;2
The other necessity, well two really, is do your research, so you know what is low, and diversify. This was highlighted when friends sold their house in the US a few years back. Not wishing to be greedy they placed the profit into 'blue chip stock- Enron. Brought nearly 100k at $76 each. Enron may sound familiar as it collapsed in one of the largest corporate failures in history. Our friends lost the lot.