Well, it could be a story where Clint Barton and Bruce Banner are on a mission together. Maybe they come across a strange lemon - like object that has some sort of strange power. And the fanfiction could revolve around how they figure out what this lemon - like thing is and how it affects their relationship and the mission at hand.
Clint Barton could be portrayed as the curious and adventurous one. He might be the first to notice the strange properties of the lemon. Bruce Banner, being the scientist, could be shown as the one who is initially hesitant but then gets really into studying the lemon. For example, Clint might pick up the lemon and say 'Hey, this thing feels different' and Bruce would start analyzing it right away.
One common theme is friendship. Given that they are both part of the Avengers, many fanfics focus on how they bond and support each other. Another theme is redemption. For example, if Bruce has an 'Hulk - out' incident that causes problems, Clint might be the one to help him through it.
There are some great Bruce Banner and Clint Barton fanfics that explore their different personalities. For example, fics that play on Bruce's scientific mind and Clint's more down - to - earth, action - oriented nature. You could also try searching on Tumblr, as there are often fanfic recs shared by the community. Just search for 'Bruce Banner Clint Barton fanfic recs' and you might find some hidden gems.
One characteristic is the intense focus on Clint Barton's personality traits within the context of a romantic relationship. In these fanfictions, his skills as an archer or his loyalty might be intertwined with the romantic plot. The 'lemon' parts, if done well, are integrated in a way that doesn't seem out of place but rather an extension of the deep emotional connection between him and the other characters. Also, they might play with different versions of the Marvel universe, like an alternate reality where Clint's relationships take a different turn.
First, think of a unique plot. Maybe Bruce is trying to find a cure for his Hulk - ness using lemons. Then, develop the characters. For Bruce, you need to capture his intelligence and his internal conflict. As for the lemon element, give it a purpose. It could be a symbol of purity in his chaotic life.
In other fanfictions, Bruce Banner could be in a situation where he's relaxing and a lemon - scented thing (like a lemonade or a lemon - scented candle) has an unexpected effect on him. It could trigger a memory or a new line of scientific thought that he then pursues, all while dealing with his own internal struggles as Bruce Banner and the potential for the Hulk to emerge.
One great Clint Barton lemon fanfiction is 'The Arrow's Mark'. It beautifully weaves a story around Clint Barton with some interesting romantic and slightly spicy elements. The author does a great job of character development, making Clint's personality shine through in the story.