For me, it's his relationship with Ygritte. Their love was passionate and real. The 'You know nothing, Jon Snow' line became iconic. It was a love that crossed the divide between the Night's Watch and the wildlings.
The discovery of the White Walkers is also crucial in Jon Snow's story. When he and his fellow rangers encounter the White Walkers and their undead army, it changes everything. It makes him realize the real threat that lies beyond the Wall and how the whole of Westeros could be in danger. This drives him to try and convince others about the danger, which is no easy task as many don't believe in the existence of the White Walkers.
One important event was when he became Lord Commander of the Night's Watch. This showed his leadership abilities. Another was his relationship with Ygritte among the wildlings. And of course, his discovery of his true parentage which could have changed the whole power structure in Westeros.
It started when he met Ygritte among the wildlings. They were initially enemies but gradually fell in love.
Well, initially, Jon Snow's journey to the Wall is a big deal. He faces a lot of challenges there among the men of the Night's Watch. His leadership skills start to develop. Then, when he goes beyond the Wall with the wildlings, he experiences a whole different world. His time with them shapes his view on the 'enemies' of the Seven Kingdoms. Later, learning that he is a Targaryen completely changes his place in the whole power struggle in Westeros.
One of the most memorable moments is when they first meet. Their eyes lock and there's an instant connection. Another moment could be when they start to trust each other during their battles against common enemies. They share a bond that goes beyond just physical attraction.
Jon Snow's story in Game of Thrones is full of twists and turns. He starts off as an outcast in his own family due to his bastard status. At the Wall, he proves himself to be a capable fighter and leader. His relationship with the wildlings, especially Ygritte, is complex. He falls in love with her while still being loyal to the Watch in a way. Later, his discovery of his true parentage shakes the very foundation of the power struggle in Westeros.
Daenerys Targaryen and Khal Drogo also had a notable love story. It started as a political marriage, but over time, Daenerys grew to love Drogo. He was a powerful and fierce warlord, and she found strength in their relationship as she started her journey to claim the Iron Throne.
The most memorable aspect is the tragic end. Jack and Rose's love was so strong but couldn't overcome the disaster of the ship sinking. It shows the power of love in the face of death.
His experiences with the White Walkers and the threats beyond the Wall really shape his character. He becomes more determined to protect Westeros. He also becomes more of a leader. When he is elected Lord Commander of the Night's Watch, he has to make tough decisions. For example, he decides to let the wildlings through the Wall to protect them from the White Walkers, which is a very controversial decision but shows his growth as a leader who thinks about the greater good.
A lot of fanfictions use the 'redemption' trope. Maybe she makes a mistake early on, like trusting the wrong person, and then has to redeem herself. There's also the 'forbidden love' trope. She could fall in love with someone she's not supposed to, like a member of a rival house. This adds a lot of drama to the story. Another popular one is the 'mentor - mentee' trope. She could be mentored by an old and wise character, like Brynden Rivers, and through that mentorship, she grows into a strong and capable leader in the world of Game of Thrones.