In a proper romance fanfiction, a good use of language is essential. The writer should be able to create a mood. For example, using soft, flowery language can enhance the romantic atmosphere. The conflict is also a key part. It could be an external conflict like family disapproval or an internal one like the character's own insecurities. And then there's the chemistry between the characters. They should have some sort of spark, something that draws them to each other, like in many popular fanfictions where the two main characters have an instant but complex connection.
Well, one key element is well - developed characters. The characters should have distinct personalities, flaws, and desires. Another is a believable plot. It can't be too far - fetched. For example, if it's a modern - day setting, suddenly having a character fly without explanation is not proper. Also, the romantic tension is crucial. It should build up gradually, like in 'Pride and Prejudice' where Elizabeth and Darcy's relationship evolves slowly over time through misunderstandings and reconciliations.
The key elements in a proper romance fanfiction include a strong emotional connection between the characters. This means they should be able to communicate their feelings, whether it's through dialogue or actions. A proper setting also matters. If it's a historical fanfiction, the details of that era should be accurate. And, of course, a satisfying ending. It doesn't have to be a happily - ever - after, but it should feel complete. For instance, if the characters have been through a lot, a bittersweet ending where they part ways but have grown from the experience can be just as good.