Spend time researching your interviewer & getting to know their work, values, and the qualifications they're looking for. Find out what the culture of the lab/organization/company is like and try to embody that through your personality and stories. Knowing the company will also be crucial for answering questions related to the position.
If you have individuals in your network that work in the position or place you're interviewing for, reach out to ask about the culture and interview process. Also, schedule some mock interviews to help prepare yourself! Having an outside perspective can help you present yourself in the best way possible.
What you say matters greatly, but your nonverbal cues can also affect the way you're perceived. Make sure to arrive early, use a confident tone, make eye contact, dress appropriately, and show respect. Your nonverbal cues can convey your attentiveness, confidence, and trustworthiness.
Prepare an answer to the classic, "Tell me about yourself..." Tailor your concise answer to the role and lab/organization/company. Here's a simple formula for structuring your response:
Many interviewers will ask questions like, "What are your strengths & weaknesses?", "Why are you interested in ________?", "What experiences do you have with ____________?"
Interviews can be daunting experiences. One way to calm your nerves is remembering that your interviewer is human, and that your interview is a conversation, albeit a professional one. Imagine yourself already in the role and know that you're qualified for it. Then, all you have to do is explain why!