Take one tired and uninspiring cardigan.
Take one cute thrifted doily (this one isn't a typical lace crocheted doily, but either kind would work nicely.)
Cut the doily in half, like so.
Pin it onto your cardie around the neckline so that it looks like a little collar.
Stitch in place with matching thread and a strong zig zag stitch.
Wear your un-boring cardie, feeling quite clever and pretty.