A while ago I wrote about a hand in the WSOP Europe where Ram Vaswani and I both played cleverly, and a parallel hand in which a mysterious German and I played like morons. I introduced the story by saying, "Ideally, you play well and your opponent plays badly."
This may have sounded like a meaningless space-filler of a sentence, but I want to return to the idea because it's more than a simple given. You shouldn't just sit there hoping your opponent will play badly - you should actively try to induce it. I'm going to spend the next couple of weeks talking about various mistakes you can help your poor opponents to make.
The first example involves making a noticeably small raise in early position. Immediately, this invites the big blind to cock up. "Ooh, it's only a bit more," he can tell himself. "I might hit the flop!" And already you have brought about a situation where someone is playing a hand, out of position and on the back foot, just because he has a sentimental attachment to the big blind he has already lost.
If someone else on the table is holding a pair, other errors may spring from your early-position small raise. Let's say you've done it with suited 4-5 or 8-10: they may fear strength and flat call (if not, you can escape cheaply). Let's say you've done it with AA or KK: someone may smell weakness and reraise. Then it's Christmas.
If you are short-stacked, you can't afford this play; better to marginal hands and move in with decent ones. But in a cash game or deep-stacked tournament, if you want to play a hand in early position, doubling the blind is a nice way to help those poor suckers misplay their own cards.