First I decided where I would be putting the finished product and cut my baseboard to the necessary length. I placed a tack every two inches so there was enough space that my necklaces didn't get tangled. I gently hammered each tack in far enough that it was not likely to fall out (and so far it has been sturdy).
Once the tacks were secure I hung the necklace holder up. The easiest way to do this is to use double sided picture hanging strips (like Command Strips).
There you go! A simple, inexpensive and cute DIY jewelry holder!