My father-in-law taught me, before he was my father-in-law. I was around 19 years old at the time and worked at it till I was about 23.
First was O/A welding with and without filler rod. Then stick welding, flat, overhead, vertical down, vertical up, horizontal. Then he made me do it all with my left hand. Then it was mig welding light and heavy material, and finally we worked on air arc gouging on huge logging equipment (I grew up in N. Michigan). We even did a bit of cast iron work.
I got a great education and had a great time working with with Joe. I love that guy!