Lay two matching feathers flat on your work surface, lining them up so that they lay on top of each other to form a little "sandwich." (Don't worry, you're not going to eat it.) Use scissors to trim away any uneven spaces where the feathers don't line up. Check the front and back sides of the feather "sandwich" to make sure you'll be looking good from every angle. Once your feathers are looking fly, you can get your craft on.
Glue the two feathers together with crafting glue. Apply a light coat of glue to the solid part that runs down the center of each feather. If you're using faux feathers, this is probably plastic; if you've got the real thing ... well, it's better not to think about what it's made of. Either way, keep the glue away from the plumage of the feather--it can make them look matted and nasty. Line the feathers up again and press them together firmly.
Cut a square of lacing, felt or leather that's long enough to cover the tip of the feathers' quill to the beginning of the feathers' plumage. This material can be covered up by other decorations later, so you can use whatever's handy, as long as it's sturdy enough to hold the feathers in place, and can be held down with glue.
Wrap this square around both quills of the glued feathers. The fabric should overlap by about 1 inch. Glue the fabric closed around the feather quills, covering them completely.
Wrap brightly colored thread, nylon, ribbon or other decoration around the fabric area to add color. Get creative--thread some beads in there for a traditional Native-American look, or go glam with crystals or other shiny stuff. Trailing ribbon ends can give a romantic look to your hair tie. Whatever you choose to make this look your own, it's ready to become part of your new Native-American hair tie accessory as soon as the glue is dry.