I have found that the process of selecting a committee to be both intimidating and challenging. The process itself is unclear. Is it appropriate to ask a faculty to serve on your committee through email? Do you need to take a class with the faculty member and establish a relationship with them? How far along in your research do you need to be?
Faculty can be intimidating as well. You have to convince them why they should spend their limited time working with you for the next few years. When I met with a potential committee member, I was drilled about my dissertation research and the roles of each committee member. I was only a second year and I had not yet thought about the specific details of my dissertation research and my department did not have set roles for each committee member. It was a very uncomfortable and disheartening experience.
Don't let this happen to you. Start looking for your committee members as soon as you can. Take classes with potential committee members or attend office hours to build relationships and learn more about these individuals before asking them to be on your committee. It is essential to find someone who has a research background or interests similar to yours. You want faculty who will take an interest in your research, not just faculty who will sit on your committee because you asked them to. You may need to look outside of your department to find committee members.
Also, read the GradShare's Committee Selection post. It has a lot of helpful tips that I wish I had known before starting the committee selection process. If you have any additional tips, share them in the comments section.