Usually in shots like this you use what is called the "rule of thirds". Do a search for the rule of thirds in the search section and you will get tons of results...or search the internet as a whole. Using this rule, the horizon would be at the bottom 1/3 of the image.
That said, another tip for the new landscape/sunset photographer...sunsets alone don't do the job. Believe me, I understand the draw of the sunset itself...the colors and textures...awesome! Unfortunately the sunrise alone in a shot is pretty boring. We've all seen sunsets and pretty colors so it becomes just another image among millions.
To make a sunset "pop", you need something of interest in the foreground or something interesting besides just the sunset and the colors...something that leads the viewer into the sunset.
Consider the sunset like frosting on a cake. Most people don't like to eat frosting all by itself. It's a bit too sugary and not very palatable. But add it to a cake and it makes the whole cake sing!
Here are two of mine as examples I use to explain this...
The first one is pretty. By itself it seems OK. But it is just another sunrise photo. Nothing special. The second one has a foreground object of interest...the pier. The pier leads the viewer into the image. The sunrise compliments the composition by adding the "frosting" and making the composition much more interesting.
And to add to the effect, look closely......the "boring" picture is actually just a crop taken from the better composition...they are both the same picture! A good example of just how important it is to thoughtfully consider where you place your elements in your photo.
And one final little tip...try to avoid using apertures smaller than f/13 or f/16. You used f/25, which will greatly affect the sharpness of the image. At that small, diffraction will cause a loss of detail and make your image look a bit out of focus. For landscape and sunrise photography, try to stick to apertures in the f/8 to f/13 range.
Hope that helps!