In Hollywood, writers of romantic films often bring lovers together in what's known as a "meet cute" - like Katharine Hepburn and Cary Grant arguing over whose golf ball it is in Bringing Up Baby, or Officer Rhodes stopping Annie for erratic driving in Bridesmaids. It certainly grabs the attention more than, say, Jane falling for Trevor who sits a few desks along in the office.
It's a trope as old as the hills that the lovers shouldn't like each other at first (cf. Elizabeth Bennett taking against Mr Darcy in Pride and Prejudice) but come to revise their opinion over the course of the plot. Personally, I think the 'not liking' thing has been done to death, so that if two characters take against each other in the early stages of a novel, readers now expect them to fall in love. And no novelist wants to be predictable.
You need some jeopardy though. There's no story if they meet, settle down and live happily till death do them part. I write historical novels and fortunately history tends to throw up some great types of jeopardy: for example, in my latest novel, The Secret Wife, Dmitri and Tatiana are separated after her family, the Romanovs, are arrested following the Russian Revolution. Wars, rebellions, plague - for writers of historical love stories these are a gift.
It's mawkish and boring if there are lots of scenes of lovers lying around telling each other how wonderful they are. You need to show their love through actions rather than tell readers that they're kissing or gazing into each other's eyes or making endless whoopie. The less smoochy stuff, the better. Think Brienne of Tarn and Jaime Lannister in Game of Thrones: you hardly ever see them in the same room but there is no doubting the strength of her feelings. Is the attraction mutual? I can't wait to find out.
Which types of character would fall for each other? In this respect, novelists have to be part psychologist. When Freud said we are attracted to idealised mirror images of ourselves, he wasn't talking about physical attributes so much as qualities we see in others and wish we had ourselves. As a very obvious example, an introvert might choose an extrovert, just as my chronically shy dad did when he married my party girl mum.
We don't necessarily have to like the protagonists in a love story, but we have to be intrigued by them. Unlikely couples, such as the morbid 18-year-old boy and the 80-year-old woman in Harold and Maude, are more interesting than any obvious match. Strange is good.
Your relationship style is often dependent on the type of parenting you experienced as a child. This is what determines whether you are needy, secure or completely commitment-phobic. Even if I don't describe a character's childhood, I have a 'back story' in my head and think about the way it has informed their personality and outlook on life. A made-up love affair has to sound authentic and fit with the other information readers are receiving about the lovers.
If you are looking for realism, the relationships that are most likely to work long-term are the ones in which the individuals have similar backgrounds and belief systems - so the odds are stacked against Hogan and his New York friend Sue in the Crocodile Dundee films. Pat and Tiffany in Silver Linings Playbook have similar backgrounds and have both struggled with their mental health, which gives them a common bond. And surviving trauma together acts as a type of relationship glue, which is the only explanation for Rose and Charlie getting it on in the final scenes of The African Queen.
What about the endings of relationships? Once readers/viewers believe in the couple, you can surprise them with a tug on the heartstrings. Who doesn't shed a tear when Ilse gets on the plane at the end of Casablanca? We yearn for Daniel and Claudette to end up together against the odds in Maggie O'Farrell's This Must Be the Place. I don't like conventional "Reader, I married him" endings so in The Secret Wife I give Dmitri difficult choices; not every reader will approve of his actions, but I hope they'll feel it's true to his character. Happy or sad, the best endings are the ones you didn't see coming but when they happen you think "Gosh, of course" because all the clues were there. There has to be an internal logic, even if there's a twist.
So a great love story has unpredictability, strange matches, long periods of separation, trauma and a twist at the end... sounds like my love life in a nutshell.
Gill Paul's novel The Secret Wife is published by Avon.