Here's a fairly straightforwards tutorial on making custom barbed wire at tabletop miniature scale - many thanks to the Hobbyhawk site for original reference ideas, but I've adjusted the scaling and polished the process a bit, so I'm writing up my own step-by-step following making custom barbed wire for my Word Bearers Dark Apostle figure.

Tools required:

• Wire - the narrower the gauge, the better. In this example I believe it was 28 gauge silver beading wire, but fine wire is available anywhere between 22 and 34 gauge commonly.
• A narrow pair of wire snips - you don't want the cutting end to be too wide or thick, as you'll be potentially be cutting in a limited space between loops of wire.
• Some sort of "rod" to use as a brace while twisting the wire - I used a wooden dowel, but a toothpick or similar could likely be gotten away with.
• A thin glue, capable of flowing into narrow gaps. I used cyanoacrylate Krazy Glue, but thinned Elmer's/Wood Glue would likely work.
• A pin vise/manual precision drill - you could likely use a pair of vice grips or pliers, but by using a pin vise you can keep it centered while twisting the wire.
• (Optional, but very useful) A ruler/tape measure with 16th" or millimeter measurement, by preference.
• (Optional, but very useful) A small, narrow pair of modeling "pliers"

Assembled tools, with the exception of the modeling pliers and tape measure (shown later.)