This is really an interesting assignment, as there are certainly differing views about what constitutes beauty, especially in the West. While there is a kind of generic standard of Western beauty, there are several categories what is considered beautiful.
The kind of beauty that most models have, for example, is not generally attainable by most women nor is it desired by most men--at least in their day-to-day lives. According to Plus Model magazine, the average model weighs twenty-three percent less than the average woman. Any model who wears a size four is too big, and she is much taller than the average woman, as well. Despite that, this is obviously one kind of beauty we value because so many industries use models, either live or in print, to sell products—and the strategy obviously works. An example of this kind of beauty might be someone like Kate Moss.
Another kind of beauty is concerned more with looking healthy and fit than being practically (or actually) anorexic. This category might include someone like Heidi Klum, Tomiko Fraser Hines, or Anna, Kournikova.
Yet another kind of Western beauty might be termed the “All-American Girl.” She is typically blond and has a heart-shaped face, pert nose, and almond-shaped eyes. Her skin is not porcelain white, but she is not dark-skinned and she is not necessarily tall. In fact, she is probably somewhat short and might even be considered rather perky. A few examples might be Hayden Panettiere, Reese Witherspoon, or (in her prime) Meg Ryan. Some darker-haired and darker-skinned examples in this category might be Vanessa Hudgens, Halle Berry, and Mila Kunis.
I assume you are only interested in female examples of beauty, but perhaps that is a stereotype. Men such as Robert Pattinson and Johnny Depp have one kind of beauty, while David Beckham and Channing Tatum have another. A third category might include Justin Timberlake and Brad Pitt.
Nearly everyone who is listed here is ultra famous, in part because people consider them to be beautiful. Your question refers to the generic standards of Western beauty, and that includes some clear expectations regarding weight; breast size (for women); muscles (for men); hair color; eye shape, and perhaps even color; nose shape;skin tone and color; height; and mouth (including lips and teeth). Search the pages of any fashion magazine or watch a televised awards show and you will see plenty of men and women who fit the criteria of Western beauty.
However, there is another way of thinking about beauty.
One psychologist [has] speculated there [are] two opposing principles of female beauty: prettiness and rarity.
Rarity, of course, refers to features rather than body type; a subtle asymmetry is also beautiful, then. Angelina Jolie is one of the most well known examples of a beautiful but slightly asymmetrical beauty.
Because the standards of beauty change and are different by cultures, we know that beauty is not really based on physical characteristics. The reality, of course, is that beauty can be found in any person because it is subjective and it encompasses more than just physical characteristics. Just as we each see beauty in different kinds of inanimate objects (such as paintings, architecture, and scenery), so we see beauty in the people we care about and love. The flaws that others might see are diminished and what is inside those we love makes them beautiful in our eyes.