One of the most crucial decisions made early on graduate school is the decision of choosing committee members. This is very important in Bio-med programs and I suppose equally important in other STEM departments as well.
So who is a committee member? A committee member is someone who provides guidance, direction and monitors the progress of a graduate student. The committee members are involved in the decision of passing you after your qualifying exam (prelims, generals e.t.c.). They are involved in your passing the dissertation (thesis defense). They play a crucial part in the progression of your thesis research and can make or mar your graduate school journey.
With all these essential duties of a committee member, it is important to choose wisely and with foresight. In choosing committee members:
1. Look for someone knowledgeable in the area of research you are interested in. This does not necessarily mean you look for the veteran in your program, nor does it necessarily mean the person must have had a dozen students graduate from their lab. What this means is that this potential committee member has an idea of what your research focus is, works or is familiar with your research interests and can contribute significantly to your progress along the way.
2. If they are all not within your area of research, then make sure they are there for a reason. For example, if you are a graduate student in a program with a focus on exposure to toxicants. Your committee members will be mostly toxicologists. However, if you are also interested in how these toxicants alter lipid regulating genes and lead to diabetes or obesity, then you might have a faculty whose work is based on lipid metabolism as a committee member as well.
3. Look for someone with a matching personality. I do not mean looking for someone who is as sanguine or melancholic as you, rather, I mean look for someone that fits into your personality frame. A quick-tempered, bossy, sharp-tongue professor who will tell you outright that your research is crap and is not going anywhere and you should give up grad sch is not exactly ideal. Unless that's what you are looking for. This point is subjective however, as some people can work well with any one. If you are the type, then feel free to choose on other merits than personality.
4. Look for someone that finds your ideas stimulating. A committee member who finds your ideas stimulating will have an interest in knowing (almost as much as you) where your work is headed. While you are giving presentations to your committee, it is always a good thing to see that they actually listen to you. You can tell because they will offer suggestions, criticize your lack of a valuable control or advise you on a different technique/method without being catty or with an overly know-all attitude.
5. Look for the perfect number of committee members for you. Obviously 2 might not be quite enough, and 5-6 might be too much. Too little and some programs might not even recognize your committee, too much and there's a higher chance of never being able to get them all together due to conflicting schedules. The right number is subjective and personal. Good luck.
6. When you have all these potential candidates on your list, then email, or schedule a meeting with them individually. Be ready to ask them a few questions, such as if they are willing to be on your committee (obviously the reason you are there but ask any way, you might be surprised how many students assumed that faculty members know exactly what's going on in the minds).
7. After all these, and you have your committee set-up, DO have a preliminary/official first meeting with them all together in one place. This is good because they can get to meet each other, you can provide a general bio to them and get their expectations of what they require of you. You can also talk about your research, not in depth but provide a general background. This might also be a good time to select your committee chair. And if you are lucky, you might even be able to set up a date for your qualifying exam.
NOTE: These are simply suggestions that I gleaned from my experience while selecting my committee members. It worked and I couldn't be more pleased with the group that I have. Based on experience, talking and making conversation with the committee at a regular interval (in my own case about 2-3 times a year) helps eliminate conflicts and miscommunication, helps put you all on the same page and none of them is left out of what I call the "communication loop".
I might edit and add some more information as I see fit.