Hit the books.
The most important strategy is to never buy something blind. This is one area where you really do need to do your homework. "I know they say a little knowledge is a dangerous thing, but no knowledge is a lot more dangerous," says Dowling. "If you don't have some knowledge, nearly everything you buy won't be right. Know your subject." And while it'll be tempting to start plugging keywords into Google, Dowling suggests your local library might be safer. "The Internet is a great source of information, but it's also a great source of disinformation," he says. "It has been used by criminals and continues to be. The Internet is great for basics. It's certainly not good if you're about to put your hand in your pocket, whether it's $50 or $5 million."