Biosimilar products must be structurally and functionally similar to their reference product. This seemingly simple expectation necessitates a unique developmental approach, which is distinct from traditional product development. The emphasis in biosimilar development lies with analytical proof of similarity, as this is the most sensitive tool to detect differences between the proposed biosimilar and the selected reference product. This paper presents a recommended pharmaceutical development model, designed to increase your probability of achieving analytical similarity, and discusses commonly observed errors made by biosimilar developers during pharmaceutical development and analytical biosimilarity assessment.