This quickie will save you some time and money if you prototype wearables or other small electronics often.
I was modding my MindFlex EEG headset and needed to connect and disconnect some small-gauge, solid-core wires frequently. I also had to deal with limited space: everything must fit inside a headphone cover. This method was born.
It's much more convenient than twisting the wires together (which often leads to shorter wires, as well as pricked fingers) – or soldering and desoldering them – or even using a small breadboard, when space and bulk are top priorities. Plus, this is cheaper than dedicating a breadboard to each section of temporary connections.
All you need is a spare female header, a teeny bit of wire, some solder, and hot glue.
First, pick up a discarded LED leg or other component lead. You know you've got these everywhere, even if you're hella fastidious. Solder it across the first 8 or so pins. This is your ground row, as many circuits require you to connect numerous components to a common ground.
As with most soldering jobs, it's easiest to tin the pins first, cover the connecting wire with a thin coat of solder, then simply lay the wire in place and run your soldering iron over it.
Next, make pairs out of the remaining pins. You can bend them toward each other first, if it makes things easier. Then, tin them and add gobbets of solder to stick them together. (Build up a globule on the soldering iron, then touch it to both pins.) These are your paired connections, whenever you need one wire to talk to another.
Finally, smudge hot glue over the whole thing, to seal it against the elements and short-circuiting. You'll need to find a happy balance of heat and header-saturation so that the glue doesn't drip off. If you like, you can lay the header down on a flat, disposable surface and drip glue through the pins to make sure everything is covered.
Once you're done prototyping, you can either remove and reuse the 2D breadboard, or simply tuck it into your project in case you need to change anything up later.
That's it! All in one step; I figure you're grown-up enough to handle this on a single page. :) Happy hacking!