Over the years, I’ve had to create a number of ethernet cables, both for my own usage, as well as for the companies I’ve worked for. It took me forever to memorize the color code for ‘straight’ ethernet cables, and I still have to look up the color combination for cross-over cables (as I don’t make a lot of them).
I’m not going to repost the article (so here’s a link to it), but the helpful guys over at “The How-To Geek” wrote a really good howto article for DIY ethernet cables. They go into what tools you would need, the color combo, etc. For the beginner who is new to cabling, this article is a good resource to reference.
I will add this disclaimer: I disagree with the length limits (long and short) they mention. From my own personal knowledge, I’ve always ran with the following length limits – Longest: 100M (300ft), Shortest (1ft). However, as numerous commentators stated, I’ve seen ethernet work at longer distances, as well as shorter. I personally carry a 4inch ethernet cable with a cross-over pigtail attachment – and it works without fail. I’ve also been involved in a 400ft+ run from one side of a manufacturing plant to another. It wasn’t a pretty run, but it worked.