Power BI consultants utilize best practices such as normalizing data, implementing star or snowflake schemas, and ensuring proper relationships between tables. They perform data profiling to understand data quality and address inconsistencies before modeling. Calculated measures and hierarchies are designed to enhance analytical capabilities. Power BI developers leverage tools like Power Query for data transformation and ensure optimal model performance by avoiding unnecessary complexity. They also document their data model structure for transparency and scalability. This method ensures a robust, efficient data model that supports the client's analytical goals.