I used the Automate... book. I must say I never found a really good resource to move from that to OOP, unit testing etc. I put a lot of scraps together for that. 'Python 3 Object Oriented Programming' by Dusty Phillips was a help, but not the answer. Lot's of Googling did that.
I started with Automate the boring stuff videos, it was a good refresher to programming concepts as well. I used to conduct Perl basics workshop for my juniors at college, replacing it with Python helped me a lot - both during preparing reference notes as well as while teaching
if finding an avenue to teach (colleagues, juniors etc) is not available, start doing projects - translating something you did in another language, some project you always wanted to do, etc
for beginners to programming, I would strongly suggest Think Python and Automate the boring stuff