1. Make a new document, maybe I'll use something rather small, 800x600px.
2. Fill background layer with black -> Shift+Backspace.
3. Go to Filter -> Noise -> Add Noise and use these settings:
4. Then, Image -> Adjustment -> Brightness / Contrast and use these settings:
5. Open Level Menu -> Ctrl+L and use these settings:
6. Duplicate background layer (Ctrl+J) and set Layer Mode to Screen, reduce Opacity to about 25%.
7. Double click on your background layer and click Ok to make it editable.
8. Make a new layer and place it under your background layer. Fill new layer with black and make your background Layer Mode to Screen.
9. Set foreground color to #062a49 and background color to #023b6c.
10. On your new layer (The lowest in hierarchy) make linear gradient like this:
11. You'll get bright star field, you can set darker colors for the gradient of course or just press Ctrl+U on gradient layer and reduce Lightness.
12. Select your base layer and once again open Level Menu and use the same settings like in step 5.
13. You can duplicate this layer once again with Screen mode to get more visible stars.
14. Let's add some details! Find some cool brushes: Rabies Star Brushset
This one is amazing, you can add pretty cool details to your star field.
15. When you use some brush from this pack, use it on new layer and try to experiment with Filter -> Sharpen -> Sharpen, sometimes it'll add more detailed stars.
More Tutorials: 
