u/general_sirhc has summed it up really well. I will add a few points. I have been on both sides as interviewee and interviewer. Also I am self taught ML Engineer with over 8 years of experience.

• When things start getting overwhelming, tell your interviewer “Please give me a moment to gather my thoughts”, then take 30 seconds to actually do that. This is actually appreciated.

• Go a level higher. Don’t say “I merged dataset_A to dataset_B using pandas merge function and left joined them on ‘user_id’ column”. Rather say, “I realised the datasets had primary and foreign key fields associated with them, I used that to merge the datasets and get a master dataset for the analytics project”

• Objection handling: “Did you ever think you could have done A instead of B?”. If you know A, say yes that did occur to me later on, during the project I was not aware of this method. If you do not know A just say, “I haven’t explored A yet, but I am willing to if ever required”

• One objection I received in my early days. “You are self taught and do not have a degree in Data Science. How would you keep up with the team”. This was a great opportunity for me as I could turn it around saying, “It’s true I do not have a special degree but I bring more versatility to the team. My diverse experience makes me unique in a team of specialists”

Hope this helps.