First, you need a great idea. Something unique and interesting that will draw readers in. Then, do some basic sketches to visualize your characters and scenes.
Don't start with an info dump. Introducing too many characters and background details at the start can be overwhelming for the reader and make it hard for them to get engaged.
One way to start off a love story is through a shared interest. Suppose there's a book club where two people have very different views on a particular book. Their heated discussion over it can be the starting point. This not only shows their personalities but also plants the seed for a potential relationship.
Well, you could begin by thinking about a unique setting or a problem that your main character has to face. Also, try to create an interesting opening scene that hooks the reader right away. Maybe it's a mystery, an action sequence, or a heartfelt moment.