First, you need to know the character of Oliver Queen well. Read the comics, watch the shows. Then, choose the other universe or character you want to cross him with. For example, if it's a Star Trek crossover, understand the rules and concepts of that universe. Next, plan out a story. Maybe Oliver is lost in the Star Trek universe and has to find his way back while dealing with Klingons or something. Start writing, don't worry too much about grammar at first, just get the story out.
One great Oliver Queen crossover fanfic is 'Oliver Queen in the DC Multiverse'. It combines Oliver's story with other DC heroes in an exciting way. Another one could be 'Oliver Queen and the Avengers Crossover' which imagines what would happen if he interacted with the Marvel heroes. And there's also 'Oliver Queen: Time - Travel Crossover' that takes him on adventures across different timelines.
Yes, there might be fanfics that focus on their non - sexual relationships such as family bonds or strategic alliances within the story's universe. For example, some fanfics could explore how they interact as family members in a more platonic way, like dealing with family business or protecting each other from common enemies.
One interesting 'Arrow Oliver Queen Learns Magic' fanfic could be 'The Green Arrow's Magical Ascent'. In this fic, Oliver discovers an ancient magic tome while on an island mission. His journey to learn magic is filled with challenges as he has to balance his newfound powers with his vigilante duties. It also delves into how his relationships with the team, like Felicity and Diggle, are affected by this new aspect of his life.
You can start by looking on fanfiction.net. It has a large collection of fanfics, and you're likely to find some great 'brainy Oliver Queen fanfic' there. Another option is Archive of Our Own (AO3). It also has a wide variety of fan - created content, including ones that focus on Oliver Queen's intelligence.
One great 'brainy Oliver Queen fanfic' is 'The Intellectual Arrow'. It delves deep into Oliver's strategic mind as he plans his vigilante activities. Another is 'Oliver Queen: The Thinker' which shows his intelligence in handling the complex politics of Star City. And 'Brainy Green Arrow' is also a good one, focusing on how his smarts help him outwit his enemies.
One way it could work is if there was some sort of magical accident that brought Oliver Queen to the wizarding world right when Harry Potter was a baby. Oliver, being a hero in his own right, would probably feel a sense of responsibility to protect the baby. He might not understand all the magic at first, but his combat skills and survival instincts would come in handy. He could teach the wizarding world some non - magical ways of self - defense, while also learning about magic himself to better protect Harry.
Yes, there could be many fanfics that focus on their sibling bond in a non - sexual way. For example, some might explore their adventures together in Star City, or how they support each other through tough times. They could be depicted as having heart - to - heart conversations about family legacy or protecting their city.