There's some really good advice in this short guide for romance writers.
What comes across most strongly is the importance of finding your style (and heat level) and committing to it. I can see the logic in that: if you attract readers of sweet romance and then swap it up for a steamy romance, your readers won't know what's coming. Of course, there's nothing to say you can't write both, but it's probably best to be absolutely clear in the cover, title and blurb about what the book is about. Also, it's vital not to look down on romantic tropes if you're trying to write romance. People like tropes because we like stories we recognise. That doesn't mean there's no room for originality, it just means you have to read everything and create something new but comforting.
There's advice on romantic tropes, the HEA ending, book lengths, finding ARC readers and trying out for Bookbub deals. Although it's a short book, the advice seems sound.