First, you need to understand the characters well. Gaara is a complex character with a troubled past, and Ino is a confident and strong - willed kunoichi. You should show their personalities clearly in your story. For example, Gaara's quiet nature and Ino's more outgoing and talkative side.
Create a compelling plot. It could be a story about how they overcome their differences. Maybe Gaara is hesitant to open up, but Ino's persistence breaks through his walls. You can also add some action and suspense, like they have to fight together against a common enemy, which brings them closer.