Gradient's parameters

Illustration of a Mailbox in Photoshop

Take the same instrument to draw a part of the mailbox's cover with the black color:

Illustration of a Mailbox in Photoshop

The instrument PenTool will help to represent an element of the mailbox's backside. The parameters are shown:

Illustration of a Mailbox in Photoshop

Blending Options-Gradient Overlay

Illustration of a Mailbox in Photoshop

Gradient's parameters

Illustration of a Mailbox in Photoshop

Take
the already known instrument to represent a highlight on the lateral mailbox's side with the white color:

Illustration of a Mailbox in Photoshop

The same instrument will help to create a small flag on the lateral side of the mailbox. Use the parameters indicated below.

Illustration of a Mailbox in Photoshop

Blending Options-Gradient Overlay

Illustration of a Mailbox in Photoshop

Gradient's parameters

Illustration of a Mailbox in Photoshop

Blending Options-Stroke

Illustration of a Mailbox in Photoshop