Fully agree on both points. 1) For anyone getting started, I think the easiest point of entry is still Descartes' Meditations. Incredibly cogent, accessible and shows in practice a way of thinking. I disagree with the last two bit that's exactly what you should do: follow a train of thought until you find better arguments.

2) formal logic seems incredibly boring, a kind of further abstraction of maths, and when I was studying it was everyone's least favorite subject. But of all things I've studied this has given me some of the most practical thinking tools that I use every day. Its like learning cheat codes for the world of reasoning.