Honestly, you can just braid a bunch of string and make yourself a choker. Or electrical cables. I also cut up an old pair of black tights. Literally find anything and tie it around your neck.
If you are new to crochet, thread crochet will be frustrating, and don't even attempt black thread. The pattern is simple... I chained a length long enough for my neck, then did a row of singles, and then two rows of alternating double and two chains to make the boxes. Final row was just a row of singles. Basically was just the fillet pattern. I finished it off with making long tassels, since those are popular now. You tie them at the back. Easy!
Above we have an in-progress shot of another choker...I wanted to go for something fancier, but honestly I think I like just the plain grungy one.
The best thing about all-fabric or all-string jewelry is that you can easily wash it. I'm looking forward to sweating these up in the summer (looking forward to summer anyway).
What's your easiest diy?