Search systems utilize keyword and semantic methods to match query terms and understand query context, respectively, often combining both for optimal results, while reranking further enhances result relevance. Traditional reranking relies on historical interaction data, but cross-encoders offer an advanced alternative by directly comparing query-result pairs for similarity, excelling in evaluating new data without extensive user interaction data. Despite being computationally expensive, cross-encoders enhance traditional systems by addressing limitations in deep text analysis and are effective for reranking subsets of data. The implementation of reranking using LlamaIndex and PostgresML demonstrates how this approach can improve search result precision, making it valuable for retrieval-augmented generation applications. The guide provides a step-by-step process for setting up and running reranking, highlighting the benefits of cross-encoders in improving search accuracy without relying heavily on third-party APIs.