We believe that you may find the following resources valuable.
The American Evaluation Association's website provides the Guiding Principles for Evaluators (the Evaluation Standards) in their entirety.
CDC Evaluation Resources Online contains information about evaluation or assistance in conducting an evaluation project. Resources are divided into groups.
The W.W. Kellogg Foundation's Evaluation Toolkit is designed to provide their grantees with guidance as they undertake evaluating and learning from their work. It is targeted primarily at those grantees who will be working with an external evaluator or conducting their own rigorous internal evaluations, but we believe anyone who is seeking to design a useful evaluation can benefit from it.