Jess Müller's guidance on improving Grafana dashboard design emphasizes the importance of simplicity and accessibility to enhance user experience. She suggests limiting the number of visualization types to facilitate quicker data comprehension, as diverse graph types can complicate interpretation and increase cognitive load. Müller also highlights the necessity of color accessibility, noting that color-blind users can be excluded if dashboards rely solely on color indicators without additional qualitative cues. She recommends using tools like accessibility checker plugins to ensure color choices are inclusive. Additionally, she advises using a consistent and limited color palette to maintain readability and direct attention effectively, utilizing salient colors for critical information. Müller encourages using company brand colors to create a more cohesive and professional appearance and invites readers to learn more by joining her webinar on dashboard design fundamentals.