First all credit goes to the people who made the original Gamer Poster.
And I was inspired by this tutorial HERE. 
I also used Here & Now Bundle by Marisa Lerin, over at Pixelscrapper.

I`m not an expert in Photoshop, and I cheat.. but when the end-results looks good I really don’t care.
This is a text-only tutorial.. someone asked me how I did it so I thought I`d share..
But if you are familiar with Photoshop.. you’ll get the steps just fine.

OK, so here are the page I made with my poster, the two photos I used and the original Gamer poster.

Btw. My best tip would be.. Always make copies – just place the extras in the bottom of the Layers. 
If something goes wrong you don’t have to start from scratch.

This is how I did it:

1. Open the main photo
2. Crop the photo until it show what I want.
3. Remove the background with the Polygonal Lasso Tool. Then a small soft eraser on the edges to make them smoother. Rename layer to “Face1″
4. Make a selection of the T-shirt with Polygonal Lasso Tool and make a copy of the T-shirt on a new layer rename this layer to “T-shirt1″. Copy to new layer. Move the copy to the bottom of the layers.
5. With “T-shirt1″ active and since the T-shirt is white and I want it black I Invert it (Image->Adjustment->Invert) Make a new empty layer above and with low Opacity I use a black soft brush and gently paint the light areas and blend.
   (Why a new empty layer? Because when it doesn’t look good I just delete the layer, make a new empty layer and try again, and again..)
   When I`m happy with this layer I leave it.. I do not Merge the layers yet.
6. “Face1″ layer: Copy to new layer. Move the copy to the bottom of the layers. With “Face1″ layer active select the eyes with Polygonal Lasso Tool and copy the eyes on a new layer. Rename the eye layer “Eyes1″ Then copy to new layer. Move the copy to the bottom of the layers.
   With “Face1″ layer active. With Clone Tool and Healing Brush I clean the skin on the “Face1″ layer.. Then copy to new layer. Move the copy to the bottom of the layers.
7. With “Face1″ layer active I play with hue/saturation.. for a warm, barely saturated sepia.
8. On a new empty layer above I play with Gradient tool (Black/Transparent) and low Opacity to get the shadows where I want them on the right side. When I`m happy and the Gradient layer is active I make a selection from the “Face1″ layer (windows: Control+ click on the “Face1″ Layer Thumbnail) and make a copy on a new layer. Rename this new layer “Gradient1″. Toss the first gradient layer. Make a new empty layer above and go over with a soft big black brush (low opacity 10-20%) on the left side. Rename this layer “Brush1″
   Copy both “Face1″ and “Brush1″ layers. Move the copies to the bottom of the layers.
9. Make a new layer below the face and t-shirt. Rename “Background”. Fill with `cold`dark grey. Make a new empty layer above the background and play with Gradient tool (White/Transparent) low opacity. Then rename the layer “Gradient2″. Then copy to new layer. Move the copy to the bottom of the layers.
10. Find the “Eyes1″ layer and move it to the top of the layers. With the “Eyes1″ layer active I zoom in close and clean the eyes with the eraser.. so only the eye and lower eyelid is visible.
    Then copy to new layer. Move the copy to the bottom of the layers.
11. With “Eye1″ active I use Elliptical Marquee Tool and make a selection around the Irises (the whole irises will not be visible, but doing it with this tool is easy.)
    Copy the irises on a new layer named “Irises1″. Then copy to new layer. Move the copy to the bottom of the layers.
12. With “Eye1″ active I play around trying to get the whites in the eye brighter.. Like Image->Adjustments->Levels.. I think I also used Gradient tool (White/Transparent) very low opacity.
13. Then with “Irises1″ active and with Rectangular Marquee Tool I make a selection of the Left Eye and the area around it, and chooseLayer via Cut. Now there are 2 iris layers. Rename them “Left Iris” and “Right Iris”. Why? Because they need different Adjustments..
    Copy both Iris layers. Move the copies to the bottom of the layers.
14. With “Left Iris” layer active, adjust, e.g. color, levels.. and add some shine.. With “Right Iris” layer active.. do the same.
    Remember the eyes may need different adjustments. Then copy both irises again and move the copies to the bottom of the layers.
15. Find “Gradient1″ layer, and make it active (but no not move it).. Find a small, soft eraser and erase with low opacity along jaw and to make some highlights e.g. under the eyebrow, cheek, nose, neck.
16. Make a group/folder of these layers in this order: (low to high) Face1, Gradient1, Brush1, Eyes1, Left Iris, Right Iris and rename the group “Face Group”
    To make it easy to edit something.. copy the “Face Group”, and move the copy all the way to the bottom of the layers.
    With “Face Group” active merge it. Rename to “Face Merged”. Then copy to new layer. Move the copy to the bottom of the layers.
17. With “Face Merged” active.. Now to the cutting.. Use Rectangular Marquee Tool, make selections and delete the selected areas.
18. Open the other photo and place it under the main photo. Rename to “Photo Below” Resize and move it around till it looks good in the cut-out.
    Then copy to new layer. Move the copy to the bottom of the layers.
19. With “Photo Below” active, edit with e.g. Levels..
20. If the “Face Merged” needs more cutting.. first copy to new layer. Move the copy to the bottom of the layers. Then with “Face Merged” active gently cut some more now..
21. Make a empty layer between “Face Merged” and “Photo Below” and rename this new layer “Cut Shadows”. And use a big, soft black brush with a low opacity and very gently add shadows in the cut.

And I think that`s it.. If something doesn’t look good.. all the copies of each step is in the bottom of the layers so it`s easy to edit.