It’s not that easy to write twins. It sounds like an interesting element to add to a story: two characters who look alike can produce a lot of conflict. It would be easy to mix them up and misunderstandings would ensue. The problem comes when there are no differences between the twins.
When I was first writing, I was a young, naive sixteen-year-old. I thought all my writing was perfect. When I was eighteen, I found a writing group, who kindly explained my writer shortcomings. In those two years, I wrote a story called The Dragon Tamer. I had twin main characters named Suzie and Emily. The story and the two lead characters were boring. It was a generic fantasy adventure, with no differences between the twins. When I wrote dialogue, it didn’t matter which character I assigned it to, because they were interchangeable.
Eventually, I abandoned the story and started work on Silver Rose, with Penelope as my main character. She’s Suzie and Emily combined into one character, with the added bonus of an actual personality. I learned the hard way that I can’t just add twins for the sake of having twins. They need to have a purpose.
I’m nearing the end of Silver Crescent. There are twin characters in this book, but I know I’ve handled them much better than my disastrous first attempt. Fiona and Rowena have distinct, separate personalities. Rowena is a constant presence throughout the story, while Fiona serves her purpose in a couple of chapters, before she disappears again. I keep them apart, so they can shine on their own. They may be sisters, but they don’t need each other to be their own character.