1. realise that 15-20% is about 2x what you can make without doing any work, since it is way in the upper percentiles of typical performance.
2. realise that anyone who gives you financial advice, if he actually KNEW how to make 15-20% would NOT BE GIVING YOU THE ADVICE IN THE FIRST PLACE. He would borrow money (including from you), make 15-20% on it, and give 3-5% to you. This applies to ALL professional money-managers, albeit with slightly different numbers.
3. realise that if you're going to make the decisions yourself, 80% of investors lose money in the long run to the 20% that make 80% of the profit.
Obviously, the only way to make money is to take control yourself. Do what the masters have done, people like Warren Buffett (buy and hold) or David Novac or Paul O'Neal (trading).
The simplest investment formula that anyone can do is to buy index trackers, directly from the manager of the tracker fund and NOT as part of a managed portfolio
and buying a set $ amount on a regular schedule e.g. monthly. This way you will do very well over the next couple of years as it continues tanking, ultimately things will turn around and you should get a return you can brag about. By the time you retire you'll be dining out on how smart you were to buy through the "dip". But don't expect 15-20% this way ... over the long haul you might expect around 12%.
Depending on how much responsibility you want to take, and how organised you are, you should consider attending courses in trading and technical analysis. One course is good, but for a clearer picture you probably want to attend several.
You can make good money buying and selling stocks - I know people who make as much as 15-20% per month - those are people who have invested a LOT of money in their education, have made very expensive mistakes, and had the discipline to school themselves to learn a system that works. Me, I am part of the 80% that haven't ... like you ...
But remember THIS forum is definitely the wrong place to get valuable investment advice!!!