  Retrieval Augmented Generation (RAG) has become one of the most popular
paradigms for enabling LLMs to access external data, and also as a mechanism
for grounding to mitigate against hallucinations. When implementing RAG you can
face several challenges like effective integration of retrieval models,
efficient representation learning, data diversity, computational efficiency
optimization, evaluation, and quality of text generation. Given all these
challenges, every day a new technique to improve RAG appears, making it
unfeasible to experiment with all combinations for your problem. In this
context, this paper presents good practices to implement, optimize, and
evaluate RAG for the Brazilian Portuguese language, focusing on the
establishment of a simple pipeline for inference and experiments. We explored a
diverse set of methods to answer questions about the first Harry Potter book.
To generate the answers we used the OpenAI's gpt-4, gpt-4-1106-preview,
gpt-3.5-turbo-1106, and Google's Gemini Pro. Focusing on the quality of the
retriever, our approach achieved an improvement of MRR@10 by 35.4% compared to
the baseline. When optimizing the input size in the application, we observed
that it is possible to further enhance it by 2.4%. Finally, we present the
complete architecture of the RAG with our recommendations. As result, we moved
from a baseline of 57.88% to a maximum relative score of 98.61%.
