[talkingcars]

Sometimes winding one wire around the other is a good place to start but agreed, it does then need to be completly covered in solder.

Have you considered teaching yourself?
Cheap soldering irons are only a few quid and you can practice on some scrap cable.
There are plenty of guides on the internet but the 2 important things are to make sure the wires and iron are clean and that you get it hot enough before applying the solder.