A commonly overlooked optimization technique is to minimize the use of volatile functions. Volatile functions, such as 'NOW' and 'RAND', recalculate every time the sheet is modified, which can slow down performance. It's best to use volatile functions only when absolutely necessary. Additionally, using the 'QUERY' function instead of multiple 'SUMIFS' or 'COUNTIFS' formulas can greatly improve performance, especially when dealing with large datasets.

One advanced technique is to use array formulas in Google Sheets. Array formulas allow you to perform calculations on multiple cells at once, reducing the need for repetitive formulas. Another technique is to use the 'FILTER' function instead of 'IF' statements when dealing with large datasets. 'FILTER' can directly extract the desired data based on certain conditions, resulting in faster calculations.