As you already know, I grew up around books. My grandfather had an expansive library, including a lot of French classics. One of his most valued possessions was his late father's Larousse Encyclopedia (dating back to 1878).
I was absolutely fascinated by that encyclopedia. It contained so much facts. Whenever I read a book set in historical times, I went to granddad's Larousse and looked up the background to the story. That way I filed away lots of tidbits in my mind.
Next to reading and writing, history was my absolute favorite. Small wonder I turned up writing historical fiction...
Most authors will tell you you need to do a lot of research when you write. That's true. But luckily for me, history holds few question marks and most of the time I don't need to look up something as I have it locked up somewhere in my brain.
When I plan a book, I set the background. Of course I turn to those periods in which I find myself the most confident. I don't often take notes - I also do them in my mind.
So writing for me is just sitting behind the pc and letting my fingers go over the keys. It sorta flows onto the paper. Yes, just like that. I write as easily as I speak - our late family doctor always said I spoke like a lawyer!
Sometimes I look up something - and not always on the internet. I still use that Larousse for facts before 1878. It's very accurate, and a trove of findings you don't find anywhere else. But most of the time I trust my good sense.
I remember when writing 'Maria Gonzalez' I sent out the story to a few proofreaders. One of them was a retired guy who had worked in intelligence. He was used to checking facts. So when I wrote somewhere in the story the sun went down around 4 pm that afternoon, he actually went to look it up - and concluded I had been correct. Seemed pretty evident to me, as in winter the sun always sets around that time!
Up to now I haven't had a reader tell me I had a fact wrong. Most of them praise me for my knowledge and thank me for sharing things with them they had not heard of before.