The general eletronic bay wiring uses #2 18-22 AWG crimp terminals and the deploy parts use #6 18-22 AWG crimp terminals for making circuit connections (note: SMT Designs 4 terminal connectors blocks require a different preparation method).
The steps here will give you a connection that you can rely on for many flights to come. A Panavise was used in these photos to hold the wire out horizontally to make assembly easier. Be sure to have the wire out far enough so the heat from soldering doesn't melt the Panavise jaws.
What you need for this
Step 1 - strip 3/16" of insulation off the end of the wire
Step 2 - slide the crimp connector on the end of the wire
Step 3 - Crimp the barrel to make a good electrical connection
Step 4 - use a soldering iron pressed lightly on the top of the barrel and melt solder on the barrel where the iron is touching it. Apply enough solder so you see it wick into the barrel.
Step 5 - remove the wire from vise and slide a 3/8" long piece of heat shrink tubing until it goes over the barrel of the connector. Use a heat gun to shrink the the tubiig around the connector end.