This is a quick and easy way to create sparkling stars or other star-like sparkles in Photoshop.
Begin with a blank background or an image that you want to add sparkles to. Dark colors work best if you want the sparkles to stand out.
Using the paintbrush tool on a new layer, with a small round brush and a soft edge, place little white dots wherever you want your sparkles to be. Vary the size of the brush for a more random look.
Create 4 duplicates of that layer.
On the first duplicate layer, use the motion blur filter at an angle of 0 degrees. The number of pixels will vary depending on the size of your image. In this lo-res test, I used a 15 pixel blur.
On the next layer, do the same thing, but at an angle of 90 degree.
Do the same thing to the last two duplicate layers, but double the number of pixels of the blur.
Set the blending style of the dot layer and all of the duplicates to screen. You now have pretty little star-like sparkles.
By experimenting with extra layers, blur amounts, blur angles, color and opacity levels, you can create variations on the basic effect.