Conceptual models are of prime importance to ensure a high level of quality in designing information systems. It has been witnessed that the majority of information systems (IS) change requests result due to deficient functionalities in the information systems. Therefore, a good analysis and design method should guarantee that conceptual models are correct and complete and easy to understand, as they are the communicating mediator between the users and the development team. Similarly, if models are complex then their extension or the incorporation of missing requirements gets very difficult for the designers. Our approach evaluates the conceptual models on multiple levels of granularity in addition to providing the corrective actions or transformations for improvement. We propose quality patterns to help the non-expert users in evaluating their models with respect to their quality goal. This paper also illustrates our approach by describing an evaluation and improvement process using a case study.