Start with a strong concept. It could be something like the OC being from another dimension and getting stuck in the Avengers' world. Then, build the story around that. Focus on the character development of both Thor and the OC. Let their relationship grow organically. Also, include some of the other Avengers to make it feel like a part of the whole universe. Write engaging dialogue and exciting action scenes to keep the readers hooked.
One great Thor x OC Avengers fanfiction is 'A New Ally'. It has an interesting plot where the OC has unique powers that catch Thor's attention. The story does a great job of integrating the OC into the Avengers' world.
One common theme is self - discovery. The male OC often has to figure out his place in the world of the Avengers and his own powers. For example, he might start off not knowing he has a special ability and then gradually discovers it through his adventures with the team.
One common theme is the discovery of the soulmate bond. The OC usually has to figure out their connection to the Avengers. Another theme is acceptance. The Avengers have to accept this new person in their midst who is their soulmate. And of course, there's often the theme of love and loyalty as the relationships develop.
A common theme is power dynamics. Since Hela is very powerful, exploring how an OC can interact with her in terms of power is often seen. For example, whether the OC is intimidated by her power or tries to gain power from her.
I really liked 'Gamer Oc's Avengers Adventure'. In this fanfiction, the Oc's gaming skills are translated into real - world superpowers within the Avengers universe. It's full of action - packed scenes and has some great interactions between the Oc and the Avengers members, like Iron Man and Captain America.
The OC can be unique by having an extraordinary talent. For example, she could be a master of an ancient martial art form that Tony has never seen before. This would not only make her stand out physically but also add an element of mystery to her character. Another way is to give her a very distinct personality trait like extreme shyness or being overly confident in a quirky way that contrasts with Tony's own personality.
Well, there's 'The Red and the Unknown'. The male OC in this one is from a different world. When he arrives in the Avengers' universe, he and Natasha have an instant attraction. But it's not just about romance. They have to fight against a common enemy, and their relationship evolves as they face different challenges together. It's a long and engaging read.
A theme that's quite popular is redemption. Maybe the OC has a troubled past, and Natasha helps them to find a new path. In the process, they fall in love. Also, there are stories where the OC has a special power or skill that complements Natasha's abilities, and they team up not just as lovers but also as a powerful duo in the Avengers. This often leads to many action - packed and emotional scenes in the fanfictions.
One popular trope is the 'fish - out - of - water' story where the oc is new to the Avengers' world and has to adapt. Another is the 'romance' trope, like the oc falling in love with one of the Avengers. The 'mentor - mentee' relationship is also common, where an Avenger takes the oc under their wing.