Allright, here is a tutorial how to create a realistic reflection on the water, quite easy one if I might say :> There are various ways how to achieve this effect really. In this tutorial we will use a displace filter.
Ok, let us begin shall we?

Open the image with water, that you would like to use. Save it as Displace.psd. We will use this file as our displacement map later in the process.

The next step is to flip a copy of the image to be reflected on the water. Choose: Image> Rotate Canvas> Flip Canvas Vertical. Use Clone Stamp Tool to correct parts around the image, like I did (you don't have to be very precise with that)

Select the Rectangular Marquee Tooll, and select part of the image (character). Hold Shift+ Ctrl+ left/ right arrow, and move the parts left or right against the image.

Then choose: Filter > Blur. You can also use the Blur Tool, and blur the image by hand, your choice really.

Choose Filter > Distort > Displace. A Displace box will appear, select a larger Horizontal Scale, and smaller Vertical Scale. That option also depends of the water surface you are using (calm water, ocean,…)
Then a dialog box will appear and ask you to choose a Displacement Map. Select Displace.psd (the file we saved in the first paragraph of tutorial).

Use the Clone Stamp Tool (selected) or Eraser to clear some parts of the reflection, the darkest areas around the image.

The last step is to set the Opacity of the Reflection Layer. Reduce it to the point where you think it looks cool <!--emo&:)--><!--endemo-->

Anyways, this concludes this tutorial. Thanks for taking time to read this. Have fun!

About the author:
My name is Primoz Vodusek I'm 21 years old and I come fr0m Slovenia. I'm a freelancer graphic designer. In my free time I'm doimg a lot of illustrations and drawing. One day I would very much like to work as a concept artist. Cheers!