Create a document of size 800x600 pixels. Make a new layer and create a gradient like what I did below. The colors used are, #02314F - #48C0ED - #001847 (from top to bottom).
Select the Brush tool and open up its Presets Brushes. Load the Wet Media Brushes and click on Append. Pick on the Watercolor Fat Tip.
Select the Gradient layer you made earlier and create a Layer Mask on it. Fill the mask with black and set the foreground color to white. Increase the Brush Size to 120px and Opacity to 60%. On the mask, paint several random horizontal strokes as shown below. Rename this layer as Sky.
Make a new layer above the Sky layer and name it as Snow Border. Using the same brush as the previous step, set the foreground color to white and Opacity to 100%. This time paint around the bottom area of the document. You can also touch up on the left and right borders.
Create a Levels Adjustments layer and set the values to 11, 0.5, 255.
Create a new layer above the Snow Border and name it as Slope. Reduce the Brush Size to 4px and Opacity to 100%. Sketch a slope like what I have done below. There is no hard rules on how to do the sketching, but will be much easier if you are using a pen tablet.
Create two slopes roughly the same size and place them side by side.
Create a new layer above the Slope and name it as Huts. Increase the Brush Size to 50px and Opacity to 50%. Briefly dot the areas on the slopes that you want the huts to be.
Then set the Brush Size to 4px and Opacity to 100%. Sketch a few huts like what I have done.
Create a new layer and name it as Snow. Using the same Brush settings, paint a few dots around to document.
Create a new layer and name it as Glitter. Draw a cross using the Pencil tool and fade the 4 corners with the Eraser.
Rotate the glitter to 45 degrees and duplicate several of it around the document.
Create a new layer and name it as Lens. Draw a large white circle and using the Eraser tool, fade the circle from its center point.
Duplicate several of this Lens layer and position them randomly over the document.
Create a new layer and name it as Santa Claus. Using the Brush tool with Size 4px and Opacity 100%, draw a brief outline of a Santa Claus.
Create a new layer below the outline and paint the white areas. Move your pen or mouse in circular motion so as to make the sketchy effect.
Repeat the same for the red areas.
Let us fill in the skin areas.
Follow by adding in the glasses.
Then we paint in some highlights and shadows.
Now select the Brush tool and pick on the preset Star 14 pixels brush. Open up the Brush Palette and key in the following settings.
Lastly, create a new layer and write your Christmas wishes to complete the design. Apply Outer Glow to the texts for a better result. That is all! Hope you enjoy the tutorial. Thanks for reading.