I'm thinking Shiva will fall in love with Raavi first after seeing how much she respects and loves Dhara and the rest of the family. I think seeing how difficult it is for Rishita to adjust to the family home will make Shiva realize how amazing Raavi is sooner, rather than later. But he will probably feel confused about his emotions, maybe even battle through some disbelief that he feels this way for his 'Maami Ki Behn Ki Beti.'
He probably will show silent forms of love to her like silently helping her whenever she is in trouble, supporting her in the family (even if the family thinks she is at fault), being patient with her whenever she is worried/wants to learn/try something new, listening to every one of her worries.
I don't see Shiva being someone with showy displays of love (otherwise, he totally would have let Raavi know about catching the matka during the haldi scene), so it might take Raavi some time to understand Shiva's admiration/love. Plus, she also needs to reconcile her feelings after realizing that her childhood dream can never become a reality.
But, I think Raavi will be the one to confess her feelings. Especially after hearing what the town thinks of him and Raavi at the wedding, I think Shiva might feel a bit insecure about their match (maybe even consider Raavi to be too good/too caring for him), plus, he might feel guilty about insulting her all throughout their childhood. So, Raavi might just have to beat it into him that they are made for each other