The "secret" to the stock market is there is no secret. The key to making money is being knowledgeable, you need to know how companies are doing, how the future looks for their market and products, etc. If you have the time to do the research and make sound choices, then you'll do well. If you mindlessly follow the advice of experts, expect to loose your shirt.
If you don't have the time, then picking a good investment adviser will be worth it to you. And you'll need to do research into the investment advisers as not all of them are worth a damn.
Just like any other professionals, sometimes you can do a better job than they can, sometimes not. Know your strengths and weaknesses and make your choices accordingly.
