Step 1
We start off with a document with a dimension of 800 by 900 pixels and a resolution of about 200 dpi. On the Tools bar, you may select the Pen Tool (P) but for me, I chose the Freeform Pen Tool though you might be better off with a Pen Tool for precision sake. I just wanted to demonstrate here that, no matter how jagged or undefined a shape is, the Pen Tool options can be used easily to create any shape desired with straighter and smooth lines.
With the Pen Tool or Freeform Pen Tool selected, choose 'Paths' on
the Pen Tool's Options bar. Now, we'll draw the top part of the mouse.
(Like I said earlier, the Pen Tool would be easier to use for those
that don't possess a steady hand).
Step 2
From the Pen Tool sub menu, select Add Anchor Point Tool to add
anchor points where necessary. You can use the mouse or directional
keys on the keyboard to move these points steadily.
Step 3
For better curves, you'll find that some anchor points have
extensions. These direction points can be dragged inwards and
outwards to create curved lines.
Step 4
The mouse is taking shape now. Zoom out (Ctrl+-) to see how smooth
and rounded the corners of the mouse are and make the adjustments on
defaulting anchor points by moving them up or down where necessary.
Step 5
We'll have to reduced some anchor points for smoother curves using the Delete Anchor Point Tool.
Step 6
Click on some more anchor points to delete and use the anchor
direction points to adjust the curves in the appropriate direction for
a more rounded shape.
Step 7
With the Paint Bucket Tool (G), fill the shape with any color as it doesnt matter. You may name this layer "mouse top."
Step 8
Double-click on the "mouse top" layer for a Layer style. Select the
Gradient Overlay Layer style and edit Gradient color as shown below:
The result:
Step 9
Still on the same layer, select a Bevel and Emboss Layer style.
The result now adds a solid shade on the mouse that follows its contours.
Step 10
The mouse is too smooth and so we'll add a faint grainy look for it.
Go to Filter>Noise>Add Noise and set of Amount of 6.5%. After the
Noise Filter's been applied, duplicate it (mouse top copy).

We have here the result:
Step 11
On the "mouse top" layer, add a Drop Shadow Layer style with its Distance at 8px, Size a 5px and an Angle of 100 degree.
Step 12
For the "mouse top copy" layer, apply an Inner Glow Layer style and reduce the layer's opacity (on the Layers Palette) to 85%.

The result:
Step 13
Go to Image>Adjustment>Brightness/Contrast and reduce the Brightness to -70.
Step 14
With the Pen Tool selected, create the bottom half of the mouse.
Step 15
Right-click still with the Pen Tool and select a black color: #0d0e10.
Step 16
Create a new layer and name it "wheel bevel." Select the Ellipse Tool (U) and draw an oblong shape and with the Free transform Tool (Ctrl+T), rotate it.

B.
Apply a Bevel and Emboss Layer style to the "wheel bevel" layer with the parameters below:
Step 17
We'll now make the bevel have a little more depth by editing its
Contour properties. With the Contour type as Cone, click on it to bring
up the Contour Editor and add points to the Contour Map as shown below:
Step 18
Add an Inner Shadow Layer style with the parameters below:
Step 19
Follow up with an Inner Glow Layer style for a soft outline around the bevel.

The result:
Step 20
Reduce the "wheel bevel" layer's opacity to 85%.
Step 21
Use the Ellipse Tool to draw a smaller ellipse within the bevel. Fill with a black color and name the layer "hollow."
Step 22
Create a new layer "line" and select the Line Tool (U) with a Weight
of 4 px. Draw a diagonal line across the most half of the mouse.
Step 23
On the Tools bar, select the Add Anchor Points Tool from Pen Tool's
sub options. Adjust the bend of the line at specific points as shown
below:
Step 24
Fill the line with a black color by right-clicking it selecting the color.

