Plated through hole (PTH) soldering is a basic skill that is necessary for anyone interested in creating any projects that use electronics beyond the consumer level. Here is a presentation I made that is useful for teaching soldering as well an instructor helper document for the first time assistive instructors.
I’ve taught kids as young as four years old (not just a couple, either!) how to solder. Given time, proper instruction and a patient, knowledgable instructor I believe that anyone can become proficient at PTH soldering.
The one crucial thing that most beginners forget to do is keeping the soldering iron tip clean. I can’t stress this enough, it leads to damaged equipment and a frustrating first experience soldering if the soldering iron is allowed to oxidize. Make sure people are cleaning their soldering tips at least every other solder joint and maybe even hit the tip with some tip tinner between students.