You can develop their relationship by exploring their different perspectives. Ahsoka is younger and more idealistic in some ways, while Anakin has seen more of the galaxy's harsh realities. By having them debate about Jedi teachings, or how to deal with the Sith, their relationship can grow as they learn from each other. For instance, Ahsoka might suggest a more peaceful solution to a problem, and Anakin could initially be skeptical but then come around to see her point.
One way is through shared secrets. For example, they could discover a hidden Jedi prophecy together and keep it a secret from the Jedi Council. This would create a special bond between them. Another way is by having them save each other's lives multiple times. Each time, their trust and respect for each other would grow.
Ahsoka can be developed by showing her growing understanding of Anakin and Padme's relationship. For example, she could start off being a bit naive about love and then gradually realize the depth of their connection. Also, her skills in the Force could be enhanced through her experiences with them. Maybe she has to face a powerful enemy alone while protecting Anakin and Padme, and this forces her to dig deeper into her Force abilities.
Their relationship can be developed through shared experiences. For example, going through a difficult battle together and having to save each other's lives. This would create a stronger bond between them.
One great Ahsoka and Anakin fanfic is 'The Apprentice's Journey'. It delves into their relationship during their time as master and apprentice. It shows Anakin's complex emotions towards Ahsoka, his pride in her growth as a Jedi, and also his protective instincts. The story is filled with action scenes that they face together, and the character development is really well - done.
You also have to consider their backstories. Anakin has his past as a slave and his insecurities about being a Jedi. Ahsoka was brought into the Jedi Order at a young age. Use these elements to create moments of connection. For instance, Anakin could share some of his experiences growing up different from the other Jedi with Ahsoka, and she could offer her own perspectives on growing up in the Order. This exchange of personal stories would strengthen their bond in the fanfic.
Their relationship could be developed uniquely by having them exchange cultural knowledge. Ahsoka sharing Jedi philosophy and Sabine teaching about Mandalorian traditions. This mutual learning can bring them closer.
The 'lemon' element can either strengthen or strain their relationship. If it's something positive like a shared discovery of a 'lemon' - shaped Force - enhancing object, it can bring them closer. But if it's a negative, like a 'lemon' representing a source of conflict or jealousy, it can cause tension. For example, if the 'lemon' is a powerful item that only one of them can use, it might create a rift between them as they struggle over it.
Ahsoka's character could be developed by showing her struggle with the more traditional Jedi ways as she teams up with Barriss. She might question some of the rules and find new ways to be a Jedi, influenced by Barriss' different perspective. For Barriss, she could develop by becoming more open - minded. Working with Ahsoka, who is often more adventurous, could make her less rigid in her thinking.
One common theme is mentorship. Anakin was Ahsoka's master, so fanfics often explore how he guided her and the lessons she learned from him. Another theme is loyalty. Their loyalty to each other, especially in difficult situations, is often a big part of these stories.
First, study their characters well. Know Anakin's impulsive nature and Ahsoka's determination. Then, come up with an interesting plot, like a new threat they have to face together. Don't be afraid to explore their emotions, both the positive and the negative ones.