Well for monetization, take all of the below with a grain of salt because my books only pay for themselves right now. My primary work is programming, so I'm by no means making a living off my writing!

The common advice I hear that resonates with me is to write "the most to-market book of your heart". If your _primary_ goal is money, it may be worth writing in a genre you know makes lots of it.

That's romance. Romance sells. Personally, I wanted to write sci-fi, but I also wanted to sell, so I write sci-fi romance. You don't _have_ to write romance to make money. I hear Thrillers is another popular category. I'm confident you can make it in pretty much any genre you choose, some might just take longer.

Genre fiction often has quite well-defined reader expectations. The trick is to figure out what readers expect in your chosen genre and then write that. A good bet is reading in the genre. Find other books that are doing well (Amazon and other retailer top-100 categories are good for this) and use them as examples. Watch out for outliers in the top-100 lists, though. Some authors are just so popular that their books will sell even if they're off market. I bet if Ruby Dixon released an off-market book, she'd be a best seller regardless. So it might be good to focus on high-to-mid-list authors who are not _huge_ staples but nevertheless consistently sell well.

I recently read a book called "7 Figure Fiction" by T. Taylor who talks about the concept of "Universal Fantasies": things that make a reader _feel_ something acutely when they read it. In Narnia, the fantasy of stepping through a closet and into a completely new world just invokes something in you. Just the thought of it kind of gives me goosebumps! Portal fantasy readers want that scene that makes them feel that. In sports romance, _something_ about having the main character wearing their love interest's jersey invokes an acute positive feeling in a reader of that genre. I bet if you read a bunch of sports romances, most of them will have that kind of scene. For the craft side, learning to recognize and put in those kinds of "Universal Fantasy" scenes can be helpful.

Then there's the marketing, which I suck at but which is unfortunately very important. One of the first things you'd want to do is start a newsletter. You can write a short "reader magnet" (can just be a short story or novella), sign up for BookFunnel, and use it to collect email addresses of potential readers. If you don't go with a reader magnet, you should _at least_ write something like a bonus scene that you offer readers at the back of your first book in exchange for a signup to your NL.

Once you do decide your genre and work out the technicalities of KU vs wide etc, before publishing you probably want to give away advance review copies of your book. Readers are more likely to click on your book if it has a star rating, so having early reviews of your new release can be very helpful. There are places that can help with this (Booksirens, Booksprout, etc), and you can also build a private ARC team (using something like your newsletter, or joining relevant FB groups where you can invite people to sign up for free early review copies).

If you listen to podcasts, there are _lots_ of author podcasts out there. One that I really liked is Six Figure Authors. They are on an indefinite hiatus now, but have a huge back catalogue of great episodes. The highlight of the podcast for me was Lindsay Buroker, a very prolific author who writes high fantasy and sci-fi. I think she dabbles in romance as well, but that wasn't her primary genre.