I got the idea to do this after I saw a picture of vintage doorknobs. My original plan was to make a coat/purse hanger using actual doorknobs, but I decided to downsize it and go for this cabinet knob jewelry hanger instead (although a vintage doorknob coat hanger may be in the future). Although I might end up moving it (I'm not sure how much I like the white wood on my white door), I'm pretty pleased with how it turned out. Also, it was so easy and cheap to do. It actually only cost $3 - way cheaper than anything else you could get.
All you need for this is one long piece of wood, a few cabinet knobs, screws, a pencil, and drill. I got my cabinet knobs, screws, and wood from a place called the ReStore, which sells old appliance/building materials. The cabinet knobs were $1 each, and I got the wood and screws for free.
Start by making pencil marks wherever you want your knobs to go. I made three, but you can make as many as you like. Make sure they are all on the same level.
Then, drill holes wherever you made your pencil marks. I had someone more experienced do this for me, because if I did it myself, I probably would have somehow ended up tearing up the entire piece of wood.
Next, choose your knobs and decide how to arrange them.
I decided to use these three, because they would be easy to attach.
Make sure you choose screws that are the right size! If they're too short or too long, then the knob won't be firmly attached, and will fall off. I got a wide variety of sizes just to be safe.
Take an appropriately size screw and push it through the back of the piece of wood.
Place the knob of your choosing onto the screw and twist it on, as tightly as possible.
Repeat this for all of the rest of your knobs.
And then your done! Just place it wherever you like (I put mine on my closet door) and nail it in.
And of course, don't forget to adorn your new jewelry hanger with your favorite jewelry! :)