Ha, ha. Me too. I am self taught and have no formal qualifications in technical writing. I failed English in the School Certificate, probably because it was all drama and poetry and Shakespeare and all that other rubbish that has very little to do with writing skills - the ability to express yourself, spelling, grammar, punctuation and capitalisation. I think I learnt from writing reports at work, some vocational training and writing for fun - writing bushwalking reports, editing an Atari user group newsletter and writing about adventures for a UK computer magazine.
After failing English in 4th form (or year 10, as it's called nowadays), I went on to get a distinction in technical communications at uni and a couple of prizes for most popular article in those computer newsletters/magazines.
Nowadays, most kids (and adults) can't even string a sentence together. I blame the education system and social media for that.
Oh, I'm a trainer, too. I like teaching people. Hence the desire to break things down into small understandable chunks, put things in the right sequence and make things as clear as possible.