Building a Portfolio

Hello,

I'm relatively new to the field of IxD/IA/UCD and was wondering what constitutes a good portfolio. Are there any examples anyone would be willing to share? 

Also, as I'm looking to build my mine and get more inxperience in the field of IxD, any information as to where I can find part-time work (as I'm currently working full-time) in the NYC area would be greatly appreciated.  I've hit up some of the usual hot spots such as eLance and Craigslist, but have not had any luck so far.

Thanks, and I look forward to your replies.

Nick