I think constant and open communication of feelings (good AND bad) and jealousies should be a lesson that stands on its own. If we don't communicate our wants, needs, frustrations etc. in a poly relationship the hurts can pile up really fast and turn something good into a train wreck.
NRE is such a great feeling! But you need to keep a tight rein on it and learn to recognize when you're decisions are being affected by NRE and remember to think about your other responsibilities (and relationships) and the responsibilities of the person you are seeing (depending on what kind of poly relationship you are part of). Also, relationships formed in the haste of NRE can often end just as quickly when difficulties arise. I've learned that taking things slow is the best policy.
Compromise is the name of the game in ANY relationship Especially in a poly relationship. 'nuff said.