In response to those who wondered how study teams work, I would say that they typically go through three main phases: Honeymoon period, conflict, and then norm&perform. First phase you believe the group is the best thing has happened to you. Then reality kicks in, and thanks to the conflict, there is growth opportunity and the possibility to define norms that ease coordination among members.
In our case, it was clearly like that, and now we have reached a plateau of performance, with norms about our performance and a high quality output.
All in all, it takes work, practice, involvement and some luck (in terms of having the right people in the team). I would say that, of all, luck might be one of the least important.
And how it feels to work in a good team? It is difficult to explain. It brings a great feeling of effective output, members committed to the outcome, effective coordination and excellent results.
The best way to illustrate the effective teamwork can be graphically:

Alternative youtube link: http://www.youtube.com/watch?v=H5MLNMgpywk
As per my previous post, I am not one to give answers to essays, but this video might give you some inspiration. Or at least, 3 minutes of classical music fun!
By the way, the guys playing are available for parties: http://www.stringfever.co.uk