The Web is currently the main way of providing computing services, reaching a larger number of users with different characteristics. As the complexity and interactivity of systems is increased, users become more demanding towards all the requirements associated to their distinct needs. Implementing the interaction requirements in the Web has become the main focus of accessibility and usability studies, describing essential design features which provide users with quality, assured systems. The focus on the users reinforced that as the number of users grows and the system became available to a wide variety of users, accessibility and usability features become even more critical to a Web application's success. In this paper, we present ACCESSA, a practical approach to rapidly improve the accessibility of existing Web systems, acting mainly in the interface design with no changes to the functional requirements of systems. The ACCESSA is based on the WCAG 2.0 guidelines and other patterns, choosing the guidelines that present lower implementation costs and represent higher severity accessibility issues.