There’s a certain formula to romance, and it all depends on the type you’re going for. Enemies to lovers, strangers to lovers, strangers to friends to lovers, friends to lovers, etc. This is more of a base that you can build with tropes you like, certain themes, subplots, and so on.
As someone who has never been in a relationship before, or even been kissed, it can be a bit discouraging because it’s different to writing something that’s fictional… like flying on a dragon. Romance is something experienced by a lot of people and readers can tell if you’ve never had a relationship before or did your research based on how it’s written (in other words, unrealistic depictions of feelings or the way how a character can act kind of thing). But once you do your research, romance becomes the easiest genre to write. 
Personally, I don’t read many books that are just romance, especially since there’s various levels of it (spice, no spice, erotica, etc.) and it can be hard to find the type you’re wanting to write. You can, however, analyze it when it’s a sub-genre in other books you may read. Most books, at least these days anyway, tend to use romance as a subplot, so it’s far easier that way if you want to consume it without being overwhelmed by the pure romance section. But, for me, I will often use movies as my research because they’re quite similar to how novels will play out, especially since some movies are based off books.
So… back to the formula! The few things you want to think about first are:
- How do these characters come to love each other?
Think about how you become friends with people. As you said, you either click with someone or you don’t. Well, in a way, it’s very similar to that, friendship, I mean. But there’s often a few things that pull people closer together such as their common interests, how they act around one another, etc.
I mean, you wouldn’t want to become friends with someone who is the complete opposite of you, judges and gossips about you, right? You want to become friends with someone who you can talk to about all sorts of things, be honest with, share things with, etc. That’s like relationships, in a way. The significant other technically is your best friend, and most of the time, they share a more intimate lifestyle with you.
But honestly, you don’t have to make a romance between two people who share that intimacy (doing the devil’s tango, kissing, etc.) because you can write about a couple who doesn’t share those qualities (Aces, for example). But if you want to add in kissing or something, it doesn’t have to be much at all. The common misconception with people who don’t know much about the romance genre is how romance is supposedly identified as having those steamy or steamy-looking scenes, but you can go an entire novel with the characters barely even touching. An example being the 1998 movie You’ve Got Mail where the love interests have their first kiss at the very, very end… when they finally get together.
But anyway, back to the main topic: find reasons for these characters to find themselves in situations where they gain feelings for one another.
- Why can’t they be together?
Romances end in happily ever afters, but in a story, there is always something in the way that makes them not have that happy ending. This is your main conflict. This can be anything from miscommunication to a problem that arises between the couple or outside of the couple. For example, in Maid of Honor, they can’t be together because the love interest is getting married when the main character finally realizes he loves his best friend. In While You Were Sleeping, she lied to the family while he was in a coma about being with him, and then falls for the brother but still can’t be with him due to that lie. In How to Lose a Guy in 10 Days, it’s not only their lies but the fact that it was all based on a bet and didn’t seem real.
- How is that resolved?
To get to the happily ever after, there has to be something that resolves the main issue, so the next thought is… how? What happened? This can be anything from compromising, to realizing they need to be together and will work it out, to simply professing their love for each other. This is mostly the same way you’d resolve any other conflict from other genres and stories, so it isn’t that different.
Now, the problem then comes down to the length because a lot of stories can be resolved quite simply, but this is also where subplots come in and stretching out the main conflict along with the other mini-conflicts. So, for example, in You’ve Got Mail, the main problem between the characters that isn’t romance related is how the female MC is losing her bookstore because of the male MC creating a massive bookstore where she’ll lose her customers. The other problem is that while the two are friends online, they are anonymous, despite knowing each other in person but being enemies. Once the two (online) wants to meet in person, the male MC finds out who she really is and uses that to his advantage by becoming friends with her in person (because offline, she hates him). As this happens, they slowly begin to fall in love with each other. But it doesn’t happen instantly because it’s slow burn—they get to know each other and find out that they aren’t as horrible as they thought (from a professional enemy standpoint).
Your subplots can be of anything from any genre, so you can keep it engaging with things happening outside of the romance, whether this has something to do with the families, friends, school or work, etc. For example, Jane the Virgin is a rom-com TV show that’s played off as a soap opera. However, it has multiple elements and layers that keeps you engaged because of all the drama that happens, even outside the romance. The main subgenre is crime, and every episode gets crazier and more twisty as it goes on.
The show is about a 20-something (she’s 23 in the first season, but she gets older as time passes) year old who accidentally gets artificially inseminated, causing her to become pregnant. But she’s a virgin (as the title states), and her boyfriend/fiance (Michael) isn’t too happy about it, but tries to be supportive in her decisions. However, the baby-daddy is Jane’s boss (Rafael), a guy she had a crush on years prior. There’s a love triangle between the three of them, and that becomes a bigger element later on. The crime part is that Michael is a detective and is looking into a crime-lord who just so happens to be Rafael’s step-mother but is secretly dating his sister. There’s also issues with Rafael’s wife/ex-wife who has a crime-related backstory with a horrid mother.
It just goes to show that you don’t have to write something that is complete romance (or have romantic themes) to keep it engaging. While your main genre should stay as romance, you can have other elements from other genres to keep readers (and yourself) interested in its continuation. 
I know you’re aromantic, but you seem to love writing, and it’s a kind of love/passion that can inspire you 
R-Rated