Introductions don't go into detail

The best advice I can give about introductions is that they shouldn't go into details yet. Even in a narrative paper where you are telling the reader a story, give an introduction that doesn't employ words like "What happened first was" because that statement should happen in the second paragraph when you launch into the body of details. With an argumentative paper, hold off on saying "One good reason to support this point is" because you don't do details until the body. Instead, any introduction should take the reader by the hand and bring him into the topic you'll be discussing. If I were comparing cats and dogs, I wouldn't start by saying "Cats are better than dogs for many reasons such as" because that sets me up to give details already. Instead, I would warm up the reader by talking about how much people love their pets and how there seems to be a "war" between pet owners, those who prefer cats and those who prefer dogs. Then I would end my intro paragraph with my thesis sentence about how cats and dogs have positives and negatives but with a closer look it is clear that cats are the superior pet. Or perhaps you think the opposite, and you would be one of those wacky dog lovers. Anyway, my point is that you can hint at what readers will find in your paper, but save the details for the body.