Begin by creating a file that would have 1024õ768px and 72dpi.
Paint the new made file with the next shown color's code - #06377A and the usual instrument applied in these cases - Paint Bucket Tool (G).
Next we shall create a new layer (Create new layer) and paint it in white color, using the earlier applied tool - Paint Bucket Tool. After that we should select the next option - Filter>Noise>Add Noise and set the parameters indicated below:
That is the result we should get on this stage:
On the same layer we shall apply now the next selection - Filter>Blur>Motion Blur
Try to make this layer looking like it is represented below, applying the Free Transform option by making a right click on the processed layer:
Select the next demonstrated parameters for this layer just for it to become half transparent after setting the parameters from below:
This is what we should get on this stage:
Create a new layer and apply the Brush Tool (B) to introduce several strokes of white color on our picture to be:
You should get the same picture from below:
Apply the next layer's parameters for the earlier made layer:
You must get the same result from next picture:
Take the Line Tool (U) and picture out the fir tree's contours on which we'll situate several small snowflakes:
Now we should download out of Internet a set of ready to use brushes, named dw_flake
Place the snowflakes on a new layer inside our made contours for the fir tree. In this case we'll get a Christmas tree made out entirely of snowflakes:
Move off now the layer containing the contours and apply on the layer containing the snowflakes the next option - Blending options>Drop Shadow, by making a double click on the left mouse's button on the layer we work with on the layers' panel:
You should get the same result from the next image:
Next we shall create the star situated on the Christmas tree's top, by applying the Custom Shape Tool (U) and choosing the star out of the option Set shape to create
Using the Direct Selection Tool (A) and pressing SHIFT button, it's possible to mark out five points inside the star and then choose the Free Transform (Ctrl+T) option to narrow out these points, directing them to the central part of the star:
Apply for the new made star the next demonstrated Blending Options parameters.
Blending Options>Drop Shadow
Blending Options>Gradient Overlay
Blending Options>Gradient Overlay>Gradient Editor
This is the picture we have got:
Applying the described method above and the same tools, it is possible to represent a second star, but this time it should have less approached points. The new star should be placed above the previous one:
This is final picture we should get!
Download Brushes here.

