4. Add Grain:
Want to add a film-like grain? Adobe Camera Raw has a much more sophisticated method for adding grain than Photoshop does. So save your image as a flattened TIFF and head to Bridge. Then go to File > Open in Camera Raw. Choose the Effects tab, and zoom in on your image to 50%. Once you increase the grain by moving the Amount slider to the right, the automatic Size and Roughness will kick in. The defaults are good for adding subtle texture, but you can increase all three sliders to make your image look really grainy.