Hot-Glue on Roses and Zip-Ties on Kittens

Here are A Few of My Favourite Things that I do when I am building a
multi-component installation.

When I need to turn a prototype into a working installation, two
important tools in my toolbox are hot-melt glue, and self-locking
cable ties (also known as "Zip Ties").

Together these techniques help to turn a jumble of wires and parts into
a robust installation that will function reliably and look professional.

Custom patch cables and headers

While pre-made "du Pont" jumper leads are convenient and inexpensive,
sometimes you want an exact length. Jumper leads typically come in
10cm, 20cm or 30cm lenths, but when you're making a permanent
installation, you want your links to be the exact length you need, to
reduce clutter. Here is a technique I learned in the days of the MIT
"Handy Board" (an early robotics experimenters' platform, popular in
the early 1990s):

First, obtain a supply of snap-off headers, female header pins, and
ribbon cable. Old parallel-ATA data cables are good, or you can buy a
roll of coloured ribbon cable. You can also cut your existing du Pont
cables to length and attach new ends.

Next hold your headers in a soldering clamp, and tin each pin.
Strip and tin your wires. Solder the wires to the pins by holding
them overlapped by 2mm and touching with the soldering iron.

Now you need to insulate the joins. Heat-shrink is good, but
fiddly. A quicker and more robust way is HOT GLUE. Heat up your glue
gun and apply a small amount of glue to completely cover all the
wires. Build the glue up onto the body of the header. Don't be
tempted to touch until it is cool.

Odd-sized headers

If you need a 14 pin header or any uncommon size that you don't have
as a one-piece header, reach into the supply of headers that you
do have.

You can either:

• Remove one pin from a large header, and then cut the header at the
  missing pin to make smaller header, or
  
• Hot-glue two or more smaller headers together to make a single
  large one
  

"SIL Gadgets"

"SIL" is an acronym for Single-In-Line, and refers to the arrangement of connection pins in single row, which is best for working with solderless breadboards and/or Arduino.

If you are working with breadboards, make up a number of cables that join a male header to various components such as switches, LEDs, speakers and batteries. When you want to test a module it's handy to have pre-wired inputs and outputs that you can re-use for temporary hook-ups.
I have a boxful of these that I've made for various devices, and some of them have been reused over and over for many years.

Pegboard lash-up installations

When your installation consists of a number of modules connected by jumper cables, an excellent way to make the lash-up installable is to cut a piece of peg-board to size and fix each module in place with cable-ties.
Don't forget, the self-adhesive backing on most breadboards is there to be used, too.

I use this pegboard technique for home automation equipment points, and for larger robots.