A good crimping tool
cable (cat5e, cat6a, cat7)
RJ45 connectors (what normal people call 'ethernet')
In this short guide, i'm going to show you how to make data cable. Specifically, cat5e UTP (unshielded twisted pair). Your useage will vary, but cat5e is good for lengths of up to 100m, and speeds of up to 1Gb/s 1000BASE-T. If you're actually putting it in walls i'd advise the use of cat6a. It's marginally more expensive, but it supports 10GBASE-T at lengths of 100m (55m for cat6 regular) providing you have the quipment to go with it, which at present is very expensive.
The wiring scheme i'll be using is 568B.
The finished product
Cut your cable to length, leaving some extra room for trimming it or mistakes unless you're really really confident in your measuring.
Make sure your cut is clean and straight. Next you'll want to strip the sheathing to expose the 4 twisted pairs. Be careful not to nip the thin sheath of any of the twisted pairs. If you do make a new cut past it and start again.
Next, roughly separate the wires into the 4 twisted pairs.
Now you'll want to untwist the tops of the pairs and line them up in order. If you're using 568B the order goes:
This is something you'll get better at each time you do it, but it will probably take you a while your first time. It doesn't take many attempts to become proficient though so stick at it.
Once you have them in roughly the correct order, you'll want to trim them so they're exactly all the same length. If you cut too much off though the wire won't reach the contacts and you'll have to start again, so be careful here.
Next is a weird step. It will either go flawlessly or it will be difficult, you need to put the flattened out cables into the RJ45 connector. While keeping the order the same and the cables straight. Fortunately the RJ45 connectors have channels in them to try and route them properly, so that helps.
Here's a picture. It's quite large
Make sure they're in the correct order and are far enough in for the contacts to enter the wire insulation. Once you're sure put it carefully in the crimping tool and clamp down. Hard. I don't think it's possible to clamp it too hardly so be sure to be firm.
Because of the double action, it crimps in two places. at the end where the contacts are (right arrow), and further down the wire (indicated by the left arrow). The latter stops the wire from slipping out of the connector.
That's it. Repeat for the other end (same wiring layout) and test it. You can buy a cable tester, or if you're lower budget (like me) just plug one end into a switch on your network and the other into a computer and see if it works. You'll want to check that it is operating at gigabit speeds if you've chosen that too.
It's worth pointing out that you can also boot the cable. This is a boot
The boot prevents the wire from being stressed too much but personally i don't bother. But they're cheap and you might want to.
I hope this helps some people, but the best way to learn this is by doing.