Right click on the Diagonal Lines layer and choose Convert to Smart Object. Right click again and choose Rasterize Layer.
Set the Fill of the Diagonal Lines layer to 0% . Add these layer styles: Drop Shadow and Bevel and Emboss.
Duplicate the Jeans Background layer, rename it Crosshatch and place it above all the other layers(Layer Menu > Arrange > Bring to Front). Go to Filter Menu > Brush Strokes > Crosshatch and set the stroke length: 16, sharpness: 14 and strength: 1. Also set the blend mode of this layer to Soft Light.
Create a new layer, name it Pre-washed effect and fill it with white color. Make sure the foreground color is set to white and the background color is set to black. Go to Filter > Render > Clouds. Set the blend mode of this layer to Soft Light.
For the final touches add a Hue/Saturation adjustment layer.
Add a Gradient Map adjustment layer and use these color tones: #2c2f35 and #7fc3fd . If you don't like blue jeans, you can of course use any color tones you want. Set the blend mode to Soft Light or Color if you want different color jeans.
In the last step, use the High Pass Filter to sharpen the image.
If you want, you can use these stitch Photoshop brushes to create realistic jeans pockets for example. So here is the final result for the denim jeans texture made from scratch in Photoshop.