Serving sizes and ranges, as suggested in Canada's Food Guide, are based on energy and nutrient requirements, and not on what is commonly thought of as a serving! It's important to see how much food makes up a serving to make sure you don't have "portion distortion". The Pocket Serving Sizer and Food Guide (Dairy Bureau of Canada, 1999) offers a great method for figuring out what a serving size actually looks like.
Other Handy Tips for picturing what servings look like:
Or, you can keep it really simple, and just make sure your plate looks like this — don't forget the fruit and milk!