Build Friendship: Learn Something Together
When you're in the process of building trust and getting to know each other, hopefully you'll also start building a close friendship with your partner. If you're going to commit to a long-term relationship and work at building true love, make sure you're doing it with someone who you not only love, but also like and enjoy spending time with.
In an extended relationship, it can be this sort of deep friendship that holds things together when times are tough or you feel like the spark is gone.
One of the best ways to build a friendship is to pursue common interests. When you're specifically working at making a casual relationship deeper, working to build common interests from the ground up can be especially effective. Thus, it will pay off for the two of you to spend some time learning something new together.