How to Assemble Cat5 Patch Cables

Strip the cable jacket back a couple inches from the end of the cable. This makes the wires easy to sort.
Sort the pairs in the order shown on the diagrams below.
Cut off the excess about 1/2 inch from the end of the jacket.
Insert the pairs into the connector. The wires should each go all the way in. The jacket should insert far enough in to be crimped.
Crimp the pins with a crimp tool
Repeat for other end.
Test your new patch cable.

If the jacket does not go into the connector, wires will not only look bad, but they will be prone to failure.
Wires un-twisted for more than 1/2 inch make a poor quality connection.
Cat5 wiring should not be run parallel to electrical wires. Cross electrical wires at 90º.