Add a coloured stripe or sash to image

[Kitmaker]

I love spending time creating my own football kits using a template. There are thousands of designs that i can manipulate but im looking to add my own.
i have two issues as shown in the picture.
I'd like to add a white stripe down the edge of the shirt that stays in right direction and how do i add a different colour stripe or sash that keeps the creases and shading. as you can see here brush just paints over the top of the image

Any tips would be helpful

For example

 

[IamSam]

Hey.

Several things to address here.

You can add the stripe's/sash's with any of the selection tools.
Here I have just used the Rectangular Marquee Tool to add a Red stripe.



I then adjust the layers blending mode to "multiply" to visualize the underlying shadows and highlights of the wrinkles.


The problem is that the stripe is too straight. You have to make it look as though it belongs.
You can use a displacement map or just warp the stripe in free transform, puppet warp, liquify, etc.
I usually draw it out using the Pen Tool.

This is exaggerated slightly for demo..


Adding a gradient helps as well.

 

[Kitmaker]

Thanks for the tip

 

[IamSam]

Thanks for the tip

You're welcome.

Here's another.

Use the Pen Tool (set to path) to add a stripe under the arm.
First create a path....

Turn the path into a selection...


On a new layer, fill the selection with the desired color...


Set the stripe layers blending mode to "Multiply"
Then add some shadow and highlight layers using the Brush Tool.
Done.