To create effective dashboards or charts in Google Sheets for visualizing monthly performance trends across multiple teams, I would start by gathering all relevant data from each team to ensure I have a comprehensive dataset. Next, I would organize this data in a structured format within Google Sheets, using columns for different metrics and rows for each month. I would then utilize pivot tables to summarize the data, allowing me to easily compare performance across teams and time periods. For visualization, I would choose appropriate chart types, such as line charts for trends over time or bar charts for comparing team performances. I would also use conditional formatting to highlight key insights or anomalies. Additionally, I would ensure the dashboard is interactive by incorporating filters and slicers, enabling users to focus on specific teams or metrics. Finally, I would regularly update the dashboard to reflect the most current data and share it with stakeholders for ongoing performance tracking and decision-making.