Silhouette is one classic method to get an artistic touch to your pictures. You may use it for book cover, or simply framed it big and hang it on your living room. I went for a short trip in Kuala Perlis, Kedah with my model (my younger brother) and there was a nice coastal line facing the sun set. We were there just in time.
Getting nice silhouette shots is easy. Just drop your exposure low enough to get the nice contrasting background, the sun reflection on the surface of the sea and put your subject in between you and the sun. Walla!

Sometimes, the sky does not have the tone that you really like to have. It could be very dull. For example, this shot below...

What you can do is adjust the color level using your photo editor program. Some program may have auto level option. Simply click it and the photo will be much better.

And here is the result...

If you like, you can add more gradient on the sky to make the image looks deeper and more natural. First, add another layer to your photo...

Then select a gradient option with transparency mode. Choose gradient type depending on your photo. Adjust the opacity as you wish. For this one, I used linear type...

Put up the gradient on top of your photo, adjust it accordingly. You can even move it up and down by pressing Ctrl button while clicking and dragging it up and down with you mouse.
And finally...

One more photo from me below.
