Please note what Katy ISD is doing with their SRP.
Read books that interest you is the first bullet point: NO required books. There are suggestions (they are using text messages for recommendations weekly as well as giving lists and other resources on their Weebly page.
Keep track of what you read. Again, there is a reminder to do that. But if kids do not keep track what happens? NOT. A. THING.
Tweet about reading. They give kids a hashtag. If kids do not tweet, what happens. NOT. A THING.
I am thrilled to help them spread the word. I think this should be a foundational example of how to establish an SRP.