During the summer, I found it extremely helpful to read as many screenplays as possible. Screenwriting is a lot different than other forms of writing, so reading professional screenplays helped me get a better feel for the craft. Here is the link to a script dump that contains tons of great screenplays including Django Unchained, Birdman, and Deadpool:

https://drive.google.com/drive/folders/0B5lHQAVEce61clFSSzVJbHR4bUk