Apply after that the Shape Tool to insert the clouds on the picture (on a new layer), which distorting level should be changed with Edit ? Free Transform (ctrl+t).



Make the layer's Opacity smaller, till 20%.



Using the same Shape Tool on a new layer, insert under the land any ornament, changing its size also.



Change the layer's Blending Mode on Overlay.



Applying a set of ready to use brushes, insert the birds after that, which brushes may be downloaded from this address: http://www.deviantart.com/deviation/15235143/ ?qo=92&q=by%3Aspiritsighs-stock&qh=sort%3Atime+-in%3Ascraps.