Often groups are curious about whether using a networking or physics library is the right way to go, or how to handle animations. Since there is no one right answer, I'm going to use the experiences and advice of past groups to help you make your decision.
At the end of the quarter you will be writing a final report, and in the report you will talk about some of your experiences. This also means that there are reports online from past groups, and I think it's instructive to browse them to see what advice groups have. Not all of it applies to everyone, since experiences can vary from group to group and year to year. But as an example, here is the final report by Group 2 (Breakneck Brigade) from 2014. It has some good advice, and enough detail and voices from group members that you can get a sense for the group's experience during the quarter:
https://docs.google.com/document/d/1tpTVPrdCbGU78ku2QFseTcw3Oe1em7s-Ww707Xj3ydE/edit?pref=2&pli=1
For graphics, networking, physics, and sound I have collected pertinent experiences from past groups that discuss the choices they made and the tradeoffs in making those choices. Use these experiences to inform your design decisions: