To begin with, go to file > new, and choose how you want the image (I chose portrait, 5×7). Choose a Christmassy foreground and background colour (I chose medium red, and a dark red).
Grab the gradient tool, and go to the top bar to choose the preset you want (I used radial). I set my darker red as the foreground colour, and chose a gradual gradient in the gradient selection box at the top left. I clicked in the middle and drew outward, and ended up with a ”spotlight” effect.
Next create a new layer, and choose the magnetic lasso tool, right click and select polygonal lasso tool. Draw a horizontal line near the bottom (shift + click to produce straight line) release shift, go up to the top, and back down to create a basic triangle.
Next, change foreground colour to something different (I chose yellow), and go to edit > fill. Select foreground colour from drop-down menu and say ok.
Hit ctrl + D to deselect and you have a yellow triangle!
The edges are much too hard, so go to filter > blur > Gaussian blur and select a high value (I chose 83).
Lower the layer opacity slightly until you have something like this.
Choose brush tool, (I used star but you can go to http://www.gavtrain.com/ts/snow.zip and download a snowflake preset. Unzip the file, and when PS is empty, drag the file into the editor. It will then be under brush presets) and from the panel at the top left, choose the star tool from the drop down. Press the button next to it (Toggle the Brush Panel) and experiment to find an effect you like.
Create a new layer, hold shift, and click at the bottom of the triangle, then the top. Continue holding shift, and click at the other bottom corner, then back where you started.
Fill in the middle of the triangle, and admire your work. The stars twinkle and look pretty, but click ctrl + J to duplicate the layer if you want them shinier and more twinkly.
Next, we need a star! Turn off the brush dynamic by un-checking the boxes in the Toggle the Brush Panel and choose a different foreground colour, I chose white. Position your brush, and click a couple of times to produce a pure, and beautiful star!
Next, we need text! Go to the txt tool, and choosse the font, colour and size of your choice. Choose a message, either personal, or simply ”Merry Christmas”.
You can also choose the same text colour as the background colour, and add a layer style to it to make it show up.
Now, you have your final Christmas card!