A data visualization consultant should prioritize tools that fit the client’s needs, data structure, and technical environment. Power BI and Tableau are popular for their ease of use, scalability, and strong visual analytics features. For clients requiring custom visualizations, D3.js or Python libraries like Matplotlib and Seaborn may be more appropriate. Google Data Studio is another option for clients using Google’s ecosystem. A consultant should also consider integration capabilities with data sources and the client's preferred platforms, ensuring seamless workflows. Ultimately, the tool should match the complexity and scale of the client’s project.