Trick Photoshop

I have seen tutorials on creating a half human half robot in Photoshop. It should not be difficult to do.
I will be creating this. We need two images for this.

You will find this image here

You will find this image here

Step 1 : Use the Magnetic Lasso, Pen Tool or the Quick Selection tool to create a selection.

Step 2 : Go to Select>Modify>Feather.

Step 3 : I have given a Feather Radius of 3. Click OK.

Step 4 : Press CTRL+J. The selection is copied and pasted on Layer1.

Step 5 : Press v (shortcut for Move Tool) and drag the engine image over the model.

Step 6 : The engine image is smaller than the model. Press CTRL+T. A selection forms. Drag a corner handle outwards. Press ENTER. The engine image covers that of the model.

Step 7 : Press ALT and click the Layer Mask button. A Black Mask forms next to the thumbnail on Layer 2.

The Foreground Color changes to White.

Step 8 : Zoom into the image.

Step 9 : Click the Brush Tool. To make the Brush small press [. To make it large press ]. To make a Brush soft press SHIFT+[ and to make it hard press SHIFT+]. We need a small soft Brush for this.

Step 10 : With a soft brush paint on the cheeks. The engine in the lower layer is revealed.

Step 11 : This is how the face  looks after the Brush work.
Step 12 : Click on the fx button. Click on Drop Shadow.
Step 13 : Click OK to apply the default settings.
Step 14 : Use the Brush Tool to paint on the arm.
Step 15 : Use the Brush Tool to paint away other parts of the body.
Step 16 : CTRL+CLICK the layer mask on Layer 2.
Step 17 : A selection of marching ants form.
Step 18 : Click the New Fill or Adjustment Layer button. Click on Hue/Saturation.

Step 19 : The Hue/Saturation adjustment layer forms. Check Colorize in Hue/Saturation. Move the Hue slider to whatever shade you want, you can use the Saturation and Lightness sliders.
Step 20 : CTRL+Click the Layer mask of the Hue/Saturation layer.
Step 21 : A selection forms as soon as you CTRL+Click. Press CTRL+SHIFT+I to inverse the selection.
Step 22 : Again click the New Fill or Adjustment layer button. Click on Hue/Saturation again.
Step 23 : A new Hue/Saturation layer forms. Check Colorize. Adjust the Hue slider first to the color you like, then the Saturation and Lightness sliders.
The finished image.
Other  photoshop tutorials are here