The next task we'll represent the wallpapers by imitating the vector style and create the illuminating effect by using different layers.

Create a new file of standard size wallpapers: File – New (ctrl+n).

Summer Party Wallpaper

Applying the Pen Tool and Fill Path command, try to represent a curve that would imitate the land on the picture to be next.

Summer Party Wallpaper

Now we have to create a new layer: Layer – New – Layer, placed under the land's layer. Then select the Rectangular Marquee Tool to mark out by turn the upper layer's part and the lowest one. The markings should be painted with the Gradient Tool.

Summer Party Wallpaper

Using the Brush Tool and downloading a set of ready to use brushes, we'll introduce on the land's layer several dancing girls and a tree.
 
The brushes that would help us to picture out the girls may be downloaded here: http://www.deviantart.com/deviation/47483316/ ?qo=4&q=in%3Aresources%2Fapplications%2Fpsbrushes+sort%3Atime+woman.

The tree's ones, from here: http://www.deviantart.com/deviation/29661536/ ?qo=8&q=boost%3Apopular+in%3Aresources%2Fapplications%2Fpsbrushes+tree.

Summer Party Wallpaper

Using a set of ready to use brushes, we'll insert also on the picture the grass on the land and several ornaments situated on the bottom. Downloading the brushes from the next address: http://www.deviantart.com/deviation/32304216/ ?qo=51&q=by%3Amelemel&qh=sort%3Atime+-in%3Ascraps.

Summer Party Wallpaper