Preparing for an engineering interview at MongoDB involves researching the company's mission, values, and goals, as well as gaining high-level knowledge of its products and Engineering teams. Candidates should also be prepared to discuss their background, interest in MongoDB, and why they are interviewing for a specific team. Technical interviews may cover topics such as concurrency, distributed systems, algorithms, system design, and language-specific coding, while behavioral interviews focus on how the candidate can contribute to the company culture. The interview process typically includes virtual interviews and an onsite interview, which may be conducted via Zoom, and candidates should be prepared with questions for their interviewers. By following these tips and being well-prepared, candidates can increase their chances of success in the interview process.