Just to add a couple of points to
@Jessica Booker 's great response:
1. Judging the building of rapport is difficult as partners have very different approaches to interviews. Whilst I think discussing personal life is a positive sign in this regard, it is definitely not conclusive. Besides Jessica's tips, I would also advise you to aim to
mirror the attitude of the interviewers and to
continuously update your approach depending on the interviewer's reactions (including body language, facial expressions etc). Some interviewers are more formal and like looking 'strict' - when speaking with them, it is good to always be maximally focused and act a bit like you are responding to a judge in court. Some may be very direct, in which case you may want to cut the use of buzzwords and exaggerated claims about yourself or the firm. Others may be a lot more relaxed and interested in learning about you as a person, and if so it would be ideal to also relax a bit as well and drop the unnecessary formalism. Point is, different approaches will work with different people and you cannot know which is the best before you enter the interview room. Start from a point of a formal yet enthusiastic attitude and then adapt based on the cues you receive.
Similarly, this applies to the substantive content of your answers as well. Some partners will appreciate really detailed commercial analysis and knowledge of the legal market - and if so, you may want to integrate that in your answers as much as you can. Others will really like detailed explanations of your non-legal experiences and ask a lot about them, in which case you should aim to bring them up more often than you would have otherwise. The idea is just that you should try to l
earn as much as you can about what works during the interview itself and not hold to a pre-established rigid approach. My best interview performances happened when I deviated from the "ideal" answers I prepared initially.
2. As Jessica said, I think in most cases it is better to build in the detail into your initial answers rather than inviting follow ups. The partners can appreciate a more complete analysis of your experiences and motivations without wanting to open a whole new discussion on them. Of course you do not want to overdo it and overload them with information, but I think most candidates worry too much about this.
If your answer is well structured and your tone is right, I think it can go well into three minutes without being considered "too long".