Your first step is to check the LEED for Homes Rating System for the requirements of each credit. For information on which materials qualify for LEED points, consider the Materials and Resources section of the LEED for Homes Rating System, especially Materials & Resources Credit 2: Environmentally Preferable Products.
A given product may earn your project a ½ point for recycled content, and another ½ point for being low-emitting. Most flooring products include a label stating the volatile organic compound (VOC) content of any adhesives or stains. If the product does not meet low-emission criteria, it may meet one of the other EPP criteria.
Flooring products such as cork can often receive credit for being made of a rapidly renewable material (½ point), and can receive an additional ½ point if EPPs cover 90% of your floor space. Additional half-points (up to 8 points total) are available for having 100% hard-surface flooring and for using local materials. Of course, your provider is always a great resource if you have questions that you cannot find answers to in the rating system or for questions about the application of a certain technique, system or material to the rating system criteria.