Interoperability is generally accomplished by developing your Web Services using the well-established guidelines for implementing Web Services and by following industry standards such as XML, WSDL, SOAP, and UDDI. However, just following Web Services standards and guidelines during the development phase of a project isn't sufficient to achieve interoperability.
The different products used for development also have to comply with many requirements such as the need to have similar implementations (data types, formats, and schemas) of the standards that you want to use. As different products are provided by different vendors, developed by several sets of people, and employ various types of underlying technologies, achieving a common understanding often becomes very difficult, which makes the products likely to be non-interoperable with each other.
