One effective way to analyze and visualize large datasets in Google Sheets is by using pivot tables and charts. Pivot tables allow you to summarize and aggregate your data, making it easier to spot trends and patterns. Pivot charts can then be created based on the pivot table, providing visual representations of the data. Additionally, you can use the FILTER function to extract specific data based on criteria and create charts using this filtered data.

For large datasets, it is recommended to use the 'Query' function, which allows you to extract specific data from multiple sheets or ranges. By combining the Query function with various aggregate functions like SUM, COUNT, AVG, etc., you can generate meaningful insights from complex data.

If the datasets are too large to handle directly in Google Sheets, you can consider utilizing Google BigQuery. BigQuery allows you to analyze massive datasets using SQL queries and then import the results into Google Sheets for further analysis and visualization.

Another method is to use add-ons such as 'Flubaroo' or 'Supermetrics' that provide advanced data analysis and visualization capabilities. These add-ons offer features like regression analysis, advanced data filtering, and more customizable chart options.