I will show you how to make a dreamy abstract background, which you could use for your web background, or technology related design. In this tutorial, I will combine many built-in filters and blending mode techniques to achieve the final result.
Create a new document. I made a 8 inches x 8 inches with white background. Then, fill the background layer with black color. Create a new layer, then also fill it with the black.
Go to the menu Filter -> Render -> Lens Fare. You drag the cross icon, to make the circle like below, then press OK.
Then, you have
In this step, still on the top layer, you use Free Transform (press Ctrl + T), to reduce the height to 28.3%.
Next, you duplicate the current layer, then rotate it for 90 degree.
Then, you choose the blending mode for this layer is Lighten.
The purpose of these steps is to create a lighting-flower. So, I continue to duplicate the layer 1, drag it to the top, rotate it about 45 degree, and applied the Lighten mode for Blending Options also.
Then, you duplicate the layer 1 again, drag it to the top, rotate it about -45 degree, then applied the Lighten for Blending Option. You will have the result like below.
Double click on the background layer (the bottom layer), then press Ok to unlock it.
Then, go to the menu Layer -> Merge Visible.
And then, press Ctrl + T to go in Free Transform mode, and increase both height and width to 225%
Go to the menu Filter -> Distort -> Wave, and applied the settings below.
Duplicate the layer and then go to the menu Filter -> Distort -> Twirl, and applied the settings below.
You also applied Screen mode for Blending Options on this new layer.
Now, you continue to duplicate the layer and rotate it again, and again to create some abstract graphics. In my works, I duplicated it about 4 times, and rotate it in each different ways to have this result.
Then press the round button (half black, half white) at the bottom of the Layer panel and select Levels to open the Levels dialogue, then you could use my numbers below. or you could play around with others.
In this step, you try with Hue/Saturation.
The final result will be like this.
(You could try to use Gaussian Blur filter to make it more mysterious if you like)