The methods used in these videos are the ones I use to produce my items. There may be other methods of tying the same knot found in some of the sites listed here.
The standard braid used in most of my key fobs. I developed this particular method, but you will find others.
Constrictor Knot I use this to tie any 'tails' I leave on a key fob. Stripping the core strands out of a short piece (12") of paracord will give you several smaller threads to work with, but they are very strong. These threads are also synthetic, so can be trimmed and melted carefully to secure them. In regular paracord or similar, this knot is useful for tying up a bundle of stuff, or closing a bag. This method of tying the knot requires you to have access to the end of whatever it is you're tying. Other methods are available in several of the web sites listed here.
Artillery Loop This is a simple way to tie a loop in a strand with at least 1 end available.
Alpine Butterfly Loop
A very secure loop used by climbers. Use it to make a loop in a line without access to either end.