Start by drawing this shape with pen tool. This will be the base of our mailbox :
Adjust the nodes of mailbox after zooming in to 200% as shown :
Apply gradient overlay and stroke in the mailbox as shown :
Due to similar white background, stroke effect of our mailbox is not visible here :)
Now, draw this shape with pen tool :
Adjust the nodes. Change the shape color to #AFAFAF.
Now, draw this shape. Use #BFBFBF as shown :
Draw a white color line with 1 pixel wide line tool as shown :
Draw this red color flag shape in our mailbox with pen tool :
Apply drop shadow in it as shown :
Draw this white color shape above the mailbox with pen tool :
Reduce its opacity around 40%. Our mailbox is ready to receive mails :)
