Ornamental help

How funny is this hedgehog? Seen at Terrain

So as I may have mentioned before, this is the first year that PB and I have a Christmas tree. We are actually going to be in Florida with PB's dad for the actual day but I loved getting a nice size tree for the house to get us in the holiday spirit. But this Jew needs some help. Ornaments. What is the tradition? Do I just buy them willy nilly or does each need a story and special moment? Do you stick to one color pallet? Also, how many packs of lights do you use? Color or white? Have bloggers and Martha Stewart made me self conscious of my own tree? I can answer that one...yes.  Help!