This is a super cheap and easy tutorial! All you'll need is leather cord, a hammer, a surface you are okay on hammering with, embroidery needles and thread and barrel clips.
Step 1: Sizing
First, you need to know how big your neck is. Wrap the cord and hold it where you need to cut to fit properly, and then cut.
Step 2: Hammering the Holes
This part is very tedious, but once you get the hang of it you'll be fine. Take your surface (and in this case is the corner of an old cork board), and hammer a hole by the edge on both sides, but a couple milimerters away to prevent from making the hole on the side, and therefore useless. Once you get your holes in (which mine has two, because I felt like it'd look cool) move on to the next step.
Step 3: Sewing the Barrel Clips
Next, get your barrel clips and your embroidery thread and the needle. Thread it like it shows in the photo, on both sides of the leather cord.
Step 4: (Optional) Accessorize
Okay, so if you do have some spare necklaces laying around you might choose to put the charm on there, or use some cool chords and string them around. Do what you want, it could be really cool! Comment what you did, and how it turned out!