Add new empty layer on the top of all layers and name it MIST. Grab the Brush Tool (B), select one of the mist brushes you've just installed and set the Opacity on 40%. Pick some light blue color and paint gently over the mountains.

Step 18 - Darkening

Left part of the image is too bright right now. You'll fix it by adding new adjustment layer Curves on the top of all layers. Set it as shown below and fill the layer mask with solid black color.

Grab the Brush Tool (B). Select some big soft round brush and set its Opacity on 40%. Paint over the areas of the image you want to make darker. Take a look on the following image to see where to paint.

Step 19 - Adding Birds

Download the brushes of birds listed in the beginning of the tutorial and install them into Photoshop.

Add new empty layer on the top of all layers and name it BIRDS. Grab the Brush Tool (B), select some of the bird brushes you've just installed and pick some dark brown color. Now simply paint the birds over the places you like. Don't overdo it to get the most realistic looking image.

Step 20 - Adding More Depth

To add more depth you'll make the edges of the photo manipulation darker to create gentle vignette. Add new adjustment layer Curves on the top of all layers and set it as on the following image.

To hide the adjustment in the center of the image grab the Brush Tool (B), select some big, soft round brush and set its Opacity on 70%. Pick black color, make sure that the layer mask of this adjustment layer is active (click on it) and paint over the horizon.

On the following image you can see how your photo manipulation should look like.

Step 21 - Adding People

If you look closely on the preview picture you can see there are some small people in the upper part of the photo manipulation. You'll paint them in this step. It's easier to paint them if you have Wacom tablet but with bit of practice and patience you can get great results with your mouse too.

Add new empty layer on the top of all layers and name it PEOPLE. Grab the Brush Tool (B), select some soft round brush and set its Diameter on 5 pixels. Set the Opacity on 100% and pick some dark blue color. Now paint people in similar way you painted them when you were little - nothing complicated, just torso, head, hands and legs. Take a look below.