In order to optimize performance when querying data from external storage in Couchbase Analytics, it is crucial to consider several factors including internet bandwidth and distance from the storage provider, number of Couchbase Analytics nodes and partitions, and prefixes and include/exclude filters. Optimal organization of data can significantly impact performance, and using prefixes and filters can help reduce the amount of data transferred, resulting in improved performance and resource utilization. By applying data organization best practices and corresponding external collection definitions, users can get the best possible performance from Couchbase Analytics when accessing external data.