Elasticsearch users aiming to optimize indexing performance should consider several best practices, including managing Java heap size, utilizing the bulk API for concurrent requests, upgrading to the latest release, and employing tools like Marvel for performance visualization. Proper hardware, such as SSDs, is crucial for achieving optimal indexing speeds, and configurations like local versus virtualized storage can significantly impact performance. Segment merging processes in Elasticsearch require careful management to avoid bottlenecks, and users should adapt index settings like refresh intervals and translog flush thresholds to balance between indexing speed and search readiness. Optimizing shard performance initially at a single-node level allows users to estimate resources needed for scaling across a cluster, ensuring efficient use of Elasticsearch's capabilities for redundancy and scalability. Users are advised to upgrade to at least version 1.3.2 to benefit from fixes and enhancements, and to consider auto-generating IDs for improved indexing rates.