First of all, on Photoshop there are always tons of ways to get the same result, I don't think mine is the best but if it can help someone who wants to get started with Photoshop, why not....
I started from this image that kyno gave me:
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I roughly cut it out (removed from its background) using the polygonal lasso tool: Image unavailable (removed by its host)
Hors sujet
Professionals most often use the pen tool instead: Image unavailable (removed by its host) which is also found in Illustrator (Adobe's vector image editing program) to make curves using a system of vectors called a Bézier curve (named after its inventor).
Personally I prefer the polygonal lasso because I find it much faster.
Personally I prefer the polygonal lasso because I find it much faster.
Once the selection is made I delete the part of the background I'm not interested in (make sure the layer isn't locked, otherwise double-click on it and confirm)
So I get this result:
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In the layer properties I set "darken" and add a new layer underneath with a neutral background (only the black areas of the character will show through, and we'll be able to fill in other layers underneath without spilling over the outline).
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I create a new layer (still below the character's layer) and make a selection (personally with the polygonal lasso).
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At the bottom of the tools palette there are 2 squares where you can select a color by clicking on them, I choose a skin tone color and go to: Edit > Fill > With foreground or background color depending on which square was selected when picking the color.
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I select a part I want to shade and go to: Selection > Modify > Feather and select a number of pixels (this number will determine how many pixels the gradient spans going from the base color to the shadow) for an image at this resolution I select 3 pixels.
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I go to: Image > Adjustments > Brightness/Contrast, I lower the brightness to get a shadow. I make another selection and do the same thing again, raising it this time to get lighter areas.
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I repeat the same process on the different parts of the body.
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Once all the areas are done, you can go back over some of them with smaller selections to add more contrast.
Once that's done we're going to increase this contrast even more by going (still on the same layer) to: Image > Adjustments > Levels and we're going to move the black arrow and the white arrow inward like this:
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Our character's skin is done. By creating a new layer we'll be able to do the same thing for the clothes with a light blue-gray base to get this:
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Same for the belt with a purple base.
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Once all the light areas are done, we're going to be able to lighten the black areas.
To do this, this time we need to create a layer, but above the character's layer.
We redo feathered selections but this time instead of playing with brightness, we're going to fill with a midnight blue for the bottom garment and a dark gray for the hair, pants and bracelets.
Then redo as before (feathered selections + brightness) to darken and lighten these areas.
We get this:
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Our character is ready, we'll be able to put together a background composition with layers instead of the "neutral background" one (in this case the brown background).
You can play with overlapping different layers, different shapes, by changing their blending mode or opacity....
You can also use brushes (brush tool) these brushes are in ".abr" format.
To install them click on the brush tool Image unavailable (removed by its host).
At the top left (next to Shape) click on the down arrow, to the right of main diameter click on a second arrow to go to "load shapes" and give the path to your ".abr" files.
You'll easily find brushes online by typing "brush photoshop" into Google.
The brushes are all the elements outside the frame of this composition:
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There you go, our Avatar is done, all we have left to do is remove the layers or imperfections we don't want to show and crop our image using this tool: Image unavailable (removed by its host)
We get this result:
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All that's left is to resize it (it's always better to work bigger, the imperfections will be less visible in the end
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There you go, that's it, for those interested here's a little video of a real pro drawing the character and using a completely different technique...
For those who liked the video you'll find more on the author's site under "Speed Paintings" HERE
que l'on retrouve également dans illustrator (prog Adobe de traitement d'images vectorielles) pour faire des courbes grâce à un système de vecteurs que l'on appelle Courbe de Bézier (provenant du nom de l'inventeur).
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For those who liked the video you'll find others on the author's site in "Speed Paintings" 
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