If you use only one item in many variations (and want to keep your website that way), you must find ways to make each page as unique as possible.
You should look at :
- The url.
- The title.
- The meta description.
- The product name and description.
- The product image name and alt attribute.
- The breadcrumb trail.
And try to customize them to make each product page unique.
Also check if a page is reachable with differents urls, if your product is reachable by its rewritten and non rewritten url, that could cause the duplicated pages problem on your website.
(For example, www.yourwebsite.com/product.php?id=02 and www.yourwebsite.com/shiny-rewritten-product-url)
If that's the case, use rel=canonical or 301 redirect to your rewritten URLs, make a sitemap with the latest ones and your duplicate pages number should go down.