In the Layers palette, select the t-shirt layer.

Choose Image > Adjustments > Brightness/Contrast and reduce the brightness by 10.

Create a new layer (Ctrl+Shift+N or Layer > New > Layer)

Using the Pen tool, create a path like shown below.

Set your foreground color to white. Then, in the Paths palette (Window > Paths), right click on the path then choose Stroke Path.

Here’s what the t-shirt looks like so far!

Repeat steps 29 and 30 for the right sleeve.

I added an abstract paint image on the t-shirt. You can add any image you like.

Create a selection like shown below. Feather the radius (Select > Modify > Feather) by 5 pixels. Now choose Select > modify > Inverse.
