• Brightness: -25
• Contrast: -30

Then activate the Eraser tool (E) and input the following values:

• Brush size: 90 px
• Hardness: 100%
• Opacity: 100%
• Flow: 100%

To reduce or increase the Hardness, right click on the image while the Eraser tool (E) is activated, then you’d see the Hardness scale, which is at default – 100%, just move the slider to the left to get 0% or to the right to get 100%.

We activated the Eraser tool (E) to erase the part of the island as shown below:

Next, let's add the castle; open the stock image: “Castle" by LilyStox. Activate the Rectangular Marquee tool (M) and create a selection area over the whole image, excluding the watermark found on the bottom of the image.

When done, move the image to the canvas using the Move tool (V). Rename this layer as: "castle". Because of its size, we would need to make it small to fit our canvas and thus fit on top of the island. To deal with that, we need to activate the Transform tool (Ctrl/Cmd + T) and resize the image as shown below:

Next, activate the Magic Wand tool (W) and left-click on the sky on the “castle" layer, (it wouldn't select all) then hit DELETE. This will accurately remove the major parts of the sky.

Now we will erase the remaining parts of the sky. Activate the Eraser tool (E) and then input the following values:

• Brush size: 20 px
• Hardness: 100%
• Opacity: 100%
• Flow: 100%

It is recommended that you adjust the zoom level to 400% or higher on the Navigator window so you could accurately erase small details.

Now, let's make those trees on the floating island look finer. Activate the Eraser tool and then right click on the canvas to bring up the Brush menu. Scroll down and pick the eraser brush which resembles that of grass; we will be using this brush to give the trees a finer finish. See image below:

When you’ve selected it, right click on the canvas while the Eraser tool is activated and then input the following settings:

• Brush size: 10px
• Hardness: 100% (default)
• Opacity: 100%
• Flow: 100%

Brush on the edges of the trees to give it some fine detail. Take note to zoom at 400% or up for you to erase accurately. See image below:

When you’re done, the edges of the trees should be similar to the image below:

Now, we will need to merge the “island" layer and the “castle" layer so we could do the necessary adjustments on both simultaneously. To merge these two layers, simply, select the “castle" and the “sky" layer and then right click on any of them to bring up the contextual menu. Once the menu opens click on Merge Layers.