Whatever method you choose, I suggest you try it at home on a chain on a bike that you have ridden some. Working with a new chain, or a worn chain, on a workbench, isn't very informative.
I've tried using my hands. I've tried using needlenose pliers. I've tried using cord. I've tried using baling wire. I've tried using the wire from a binder clip. I've tried all DIY methods I could discover that promised to open a quick link, hoping to find a method that was simple and reliable. None of them worked for me on 10 and 11 speed KMC master links. I have Park Tool master link pliers I use at home, and carry Wolf Tooth master link pliers in my on-bike took kit. They both work well. I'm still on the lookout for something better (smaller, lighter) for use on the side of the road, but haven't found it yet.