When I'm coming up with ideas for a book, it isn't just a case of letting my imagination run wild and see what happens. There are moments like that sometimes though lol.
Once I have decided on the setting for my story, for example LONDON, I then take the knowledge I already have AND do research. In this case, it was to help me decide which of the hundreds of landmarks in London that Jeremy is going to visit and the logistics of the trip.
So whilst I want the story to be fun and entertaining and of course, contain moments where you, as the reader, are asked to suspend disbelief, BUT I also want it to be realistic and mildly educational, in the least obvious way possible lol.
I know not every writer writes this way. Some fictional stories are 100% made up and contain very little realism at all and all the normal rules are out the window... and that's absolutely fine.
Some writers write in a very factual, non-fictional way, where everything is referenced and real... and that's all good too.
Me, I'm somewhere in the middle. I want the reader to thoroughly enjoy the story, as well as coming away with a little fun fact to share with friends or to have sparked a new interest in something and maybe learnt a new word or two along the way. Balance.