So, firstly we have to create a new file (File>New) that would have 1024×768 px and 72 dpi. Choosing the Rectangle Tool (U), stretch on the object the whole page and set the here demonstrated Blending Options>Gradient Overlay for it.
You may see the result we’ve got at this moment:
Create a new layer and select the next function: Filter>Render>Clouds.
Next we’ll change the parameter on the Layers palette.
You must have the same picture presented below:
Make a right moue’s click n the picture and choose the Free Transform selection.
…and stretch out horizontally the layer: After that we have to select Filter>Blur>Box Blur…