The product description pages should incorporate long tail keywords that are laser specific. If your visitor clicked on a link for "Bermuda shorts" on the category page, you'll want to get as detailed as possible, so your customer can make the decision to buy.
For instance, a keyphrase such as "Liz Claiborne pastel plaid Bermuda shorts" would be perfect for a product description because it is, well, descriptive. Long? Yes, it is a long phrase. Most long-tail keywords will be. But the further into the sales process a customer gets, the more specific their searches will be. Chances are, someone who has decided she wants pastel plaid shorts will use a phrase like the one above instead of something like "Bermuda shorts."
Here's a plus: Because long-tail phrases are much less competitive than broader terms, you stand a better shot at getting ranked highly for them.
A Word on Linking
Here's where some copywriters get confused. When you use links in anchor text, you're giving credit to the page being linked to. For instance, if you have a category page for shorts, you would want to use the keyphrase "Bermuda shorts" in the anchor text of a link that pointed to the Bermuda shorts page. That way, the Bermuda shorts page gets credit for the link. The link would be of no (or very little) value to the general shorts page.
When you take note of the navigation and purchase cycle of your visitors, you begin to see why this simple strategy for keyword placement works so well. Using more specific terms as you write more specific copy helps usher visitors from the front door to the checkout counter with ease while also boosting your search engine rankings.