Severus spent a lot of time reading about the Defense against the Dark Arts. He attempted very carefully to discover ways of efficiently fighting hexes. He recalled many curses he'd created on his own and wondered if his knowledge would be good the other way around. It was the best way for him to express interest in the dark arts without stepping over the territory he'd set for himself. There was obviously some danger in Lily's future. He had no idea what, but surely if he tried hard enough he could save her.
Lily and he shared one very similar talent: potions. He felt very close to her while they practiced together and Professor Slughorn was typically forced to separate them, as they were more often than not so capable by themselves they outperformed everyone else. Splitting them up left the rest a fair shot, but it made Severus feel like one of his joys was perhaps not so bad. His knowledge of potions was very expansive and the opportunity to share it with Lily was very enjoyable. He shared every class with her and resisted the urge to crowd her and be with her all the time. He liked to see her happy.
He was pleasantly surprised one day in herbology when she scuttled over to him. "Mind if I work with you today Sev?" She smiled happily at him and he felt his cheeks redden. "Of course Lily" In making this decision, he'd become happier than he'd ever been in his whole life. He didn't like how smug some of the other Gryffindors were, but he was far from the most down trodden or weak. Peter Pettigrew for instance was very shy and picked on frequently. James Potter liked to laugh during potions when Lily and Snape always did the best, the Slytherins never quite matched them. He was the most arrogant aside from Black, but he tended to poke fun at Slytherins and respected pretty much all of his fellow Gryffindors.
He wondered for a moment if he and Lily could be like this forever.