The best way to set aside a place for various similar things you might need but won't be using soon.
Perhaps three categories... utility/emergency (flashlights, candles, etc), financial/informative (social security card, past bills, bank statements, etc), and personal (cards, gifts from others, your diploma, pictures, etc).
Also, the best way to be in life is to simply not be sentimental or materialistic. Basically, throw away or sell anything you don't need or that you're finished with. The less you have, the less you have to organize. How much of what you have do you need or use on a regular basis?
EDIT: All of the stuff you listed should go in the trash, except for the scarves and Christmas tree. The others have uses, but aren't optimal and are easily replaced with something that serves the same function better.
About garbage bag ties specifically... you really don't need these. They're fairly useless. The best way to tie off a garbage bag is by tying a knot on the top using the bag itself.