First, start a new 800x400 with transparent layer. Get the gradient tool (press 'G') and make a gradient for the sky.
Next, create a new layer and call it "sea" and colour the sea black.
Next, create another layer and call it "sun". Make a small, white circle (whether using a big brush or pen too, etc.). Make sure its white. Put this layer underneath the 'sea' layer.
OK, now to give the sun a little sunray. now right-click the 'sun' layer and select "Blending Options". Click on "Outer glow" and do this:
Play around with the sliders until you get a good glow. Compare your current progress to mine if you want:
Next, press Ctrl + Shift + N to make a new layer and bring it just underneath the 'sun' layer. Combine the 'sun' layer and this new layer by linking it and pressing Ctrl + E. This will get rid of the "Blending Options" arrow but still maintain the effects. Call this new layer 'sun' and duplicate it.
Bring 'sun copy' layer on top of the sea layer and press Ctrl + G. Your 'Layers' window should look like this:
Now, go to filters > liquify (or press Shift + Ctrl+ X) and play around with the 'sun copy' layer until it looks something like this:
OK, now that we have our basic sunset, let's make the sea a little more sea-like. The easiest way to do this is to make a custom brush by pressing 'B' (or select the brush tool, select a 1 pixel brush and go to Window > Brushes. OK, time for some settings:
Click "Brush Tip Shape" and at the very bottom of the popup window, you see a slider titled "Spacing". Check the box and make it 1000%.
Next, click on "Shape Dynamics" and select the drop-down menu called "Size Jitter" and select "fade", 90%.
Next, click "Scattering". in that window, check the "Both Axes" box and slide the "Scattering" slider to maximum. Set "Count" to 1 and "Count Jitter" to max.
Next, "Colour Dynamics". Set everything to 0% and on the drop-down menu titled "Control", select "fade", 50%.
Next, "Other dynamics". On the opacity drop-down menu, select "fade", 75%.
OK, now create a new layer on top of 'ocean' layer and group it. Call it "detail" or somehting. Now select a yellow colour for foreground and red for background. Next, make a series of horizontal strokes on that new layer, starting from the centre of the sun's reflection. IT should look something like this:
Next, set your brush's opacity to about 60% and change the foreground colour to orange. now start brushing some more dots, this time further away from the sun. Then go to "Blending Options" again and do this:
Almost done. Now time for some clouds. To make clouds, simply get a new layer and big-ish brush (around 35 px), set foreground colour to white and play around with the scatter, opacity and size. Make sure you fade the size and scatter. Then start making clouds. Vary your brush size. Next, go to filter > gaussian blur. Play around with the setitng and you should have something like this:
Next, Motion blur the clouds. Make sure the angle is horizontal (0 degrees). Now to colour it. Create a new layer and group it with the 'cloud' layer (Ctrl + G).
Go to your gradient tool and pick a gradient like this:
Make a radial gradient from the centre of the sun to the edge of the picture.
And... you're done! If your result is significantly different to mine, let me know as I take lots of shortcuts and cut some obvious steps. Here is my result:
A tutorial by Elmo.