Hi all, this tutorial was fisrt made by overlord in french, so i'm going to translate it for those who don't read french 
How to make a shirt for your tux
Overlord tried to make this tutorial as simple as it could be, so he decided to give us the models which will compose the shirt like normal layers. He decided that because he thought that the most important things were the reflect and the shadows.
With these models, ,you will be able to create a shirt, a T-shirt, or any other clothes
Here're the models :
First of all, this tutorial will show you were to put the models on your tux
1. Open your tux (your psd or a png)
2. Open the models
3. If you're using a psd for your tux, be sure you're working on the top layer.
Then click on the thumbnails of the models layers and drag'n'drop them on your tux's canvas.
4. Rename the newly created layers "Body shirt model" and "Left collar model"
5. Duplicate the "Left collar model" layer and name the new one "Right collar model", then go to Edit > Transform > Flip horinzontal.
6. Now, move your three layers so that you see something like that :
Now we are going to colorize the shirt, and put it in relief
We'll start with the body :
1. Select the "Body shirt model" layer and create a new one, by pressing Ctrl+Shift+N, and name it "Body shirt".
2. Ctrl+Click on the "Body shirt model" layer's thumbnail to have its shape as your selection.
3. Double-click on your foreground color and enter these values :
R:101 j'ai:140 B:211 (or #658CD3)
And fill your selection with this new color by pressing Alt+Delete (this color is just an example, you can use any other color, just use your imgination 
)
4. Make the "Body shirt model" layer become invisible by clicking on the little eye next to it's thumbnail.
5. Be sure you're working on the "Body shirt" layer, create a new layer called "Body shirt shadow"
6. Select black as your foreground color.
7. Choose the gradient tool, and the Foreground to transparent gradient.
Select the reflected gradient, and check the Reverse checkbox.
8. Ctrl+click on the "Body shirt" layer's thumbnail to have its shape as a selection.
9. Make a grdient by clicking on A and relesing on B, like below :
Tip: holding Shift while you're drawing a gradient will make this gradient be straight
10. Put the "Body shirt shadow" layer's opacity to 40%.
You should have something like this :
We are now going to create the reflmects on the sleeves.
11. Create a new layer called "Left sleeve reflect"
12. Choose the poly gonal lasso tool
13. Draw a selection which ressembles to this one (if you zoom, it will be easier)
14. Put white as your foreground color.
15. Select the gradient tool, uncheck the Reverse checkbox, choose a linear gradient (instead of a reflected one), and be sure you're still using the Foreground to transparent gradient.
16. Draw a gradient from A to B, like on this image :
17. Deselect by pressing Ctrl+D
You should obtain this :
18. Re-select the polygonal lasso tool.
19. make a selection like this one :
And hit delete.
20. Put the "Left sleeve reflect" layer's opacity to 50%
21. If you have all the layers that compose the tux, Ctrl+Click on the "Body" layer's thumbnail to have its shape as your selection.
If you're using a png, use the elliptical marquee tool and Select > transform selection, to have an selection that folows the tux's body :
22. Delete and deselect.
23. Duplicate the "Left sleeve reflect" layer, and name the new one "Right sleeve reflect.
24. Now go to Edit > Transform > Flip horizontal.
25. Move the right sleeve reflect on the right sleeve, like here :
26. Ctrl+Click on the "Body shirt" layer's thumbnail.
27. Click on the "Body shirt shadow" layer and create a new layer called "Body shirt reflect"
28. Choose the gradient tool and The radial gradient option.
29. draw a gradient from A to B like on the image :
30. Reduce the layer's opacity to 35%
You should see this :
If you want a T-shirt, you can stop here, and you only have to make the collars layers become invisible by clicking on the little eyes next to their thumbnail.
If you want a shirt, you have to continue
31. Ctrl+Click on the "Left collar base" layer's thumbnail
32. Be sure you're working on the "Left collar base" layer, and cretae a new layer named "Left collar"
33. Change your foreground color to : R:101 j'ai:140 B:211 (or #658CD3)
And fill the selection with it.
34. Create a new layer called "Left collar shadow"
35. Change your foreground color to Black
36. Choose the grdient tool and the linear gradient mode
37. DRaw the gradient from A to B
You should see that :
38. Put the layer's opacity to 30%
