It's like a facelift! Just keep it on the simple side because a nip here, a tuck there, a bit of plumage there, and suddenly you look like Jocelyn Wildenstein, understand? Have I mentioned I have this little fur collar collecting problem?
Collars like these are everywhere on ebay, not to mention thrift shops and hanging out on old coats. Don't be afraid to scavenge: Denning and Fourcade (the design kings of opulent, style Rothschild interiors of yetseryear) used fur scraps from old coats to piece together an entire rug. You can find really lush ones this way; just avoid dry patches like the plague.
Basics that have personality (multiple personalities, really):
Simple equation, see?