Tutorial 3, written in PSCS but will translate to other versions of PS
How to go from this to 
01. Take your base pic and crop it to 100x100.
02. Filter >Sharpen >>Unsharp Mask...
Settings: Amount - 50% Radius - 2.0 pixels Threshold - 5 levels
I sharpened my pic twice but this will vary from picture to picture, you will know you've gone too far if the picture goes very white/shiny/pixelated around the edges. This is your base.
Good Base
Oversharpened Base
03. Duplicate your base twice, set both layers to Soft Light 100% Opacity 100% fill, leave the first duplicated layer (the one in the middle) as is, desaturate the top layer by going to Image> Adjustments >>Desaturate.
Now you should have something like this:
If your image seems too dark, duplicate the base again (leave it as the second layer, below your soft light layers) and set it to screen, play with the opacity until it looks good.
04. Time to play with curves. I know a lot of people find curves scary but really, they aren't, they are simply another tool for coloring an image. I know nothing about the technicalities of Photoshop and I can use them so you should be able to too. The main thing to understand is that no two images will respond the same way to curves.
The following two images have been colored using the exact same .acv (curves) file (right click, save as if you want to play with this file):
>>>
>>>
Curves are more of an experiment than anything.
So open a new curves layer Layer > New Adjustment Layer >> Curves
The basic idea is that the RGB channel changes the overall color of the image, as well as the brightness and contrast of the image, placing different points on the graph will effect different parts of the image (the lowlights (lower part of the graph), highlights (upper part of the graph) and midtones (middle of the graph)).
The other channels, red, blue and green change the brightness and contrast of that color, as well as it's strength. Dragging the points on the graph to the left of center will make the image more Red, Green or Blue depending on your channel, dragging the points on the graph to the right of center will make the image less red, green or blue but instead will make the image more cyan, magenta or yellow. Again picking different points in the graph will effect different parts of the image.
This is my curves file for this icon, all my curves files for icons like this are variations on this, so download this file and have a play with it. - right click, save as.
To open .acv files save the file to somewhere you'll remember, then open the curves window and click on load.
Don't be afraid to play with this file, move the plots on the graph around until you get something that looks like this:
You want a bright, yellowish effect.
5. Open up a gradient map Layer > New Adjustment Layer >> Gradient Map
This is the gradient I used:
There is no way of saving this as a gradient so instead you can use a similar gradient you already have or you can recreate this gradient by setting your background color to the green shade (#D7EFB9) and your foreground color to the brown shade (#C9BCB7) then selecting the foreground to background gradient, the very first one. After you have your gradient picked click on OK.
You should now have something like this:
Set this layer to saturate, flatten/merge all and your done.
The most important thing is to experiment, try a different gradient or different curves settings and have fun!
More examples:
...
All examples in this tutorial are up for grabs, just credit jaymakesicons.
01. Take your base pic and crop it to 100x100.
02. Filter >Sharpen >>Unsharp Mask...
Settings: Amount - 50% Radius - 2.0 pixels Threshold - 5 levels
I sharpened my pic twice but this will vary from picture to picture, you will know you've gone too far if the picture goes very white/shiny/pixelated around the edges. This is your base.
Good Base
Oversharpened Base
03. Duplicate your base twice, set both layers to Soft Light 100% Opacity 100% fill, leave the first duplicated layer (the one in the middle) as is, desaturate the top layer by going to Image> Adjustments >>Desaturate.
Now you should have something like this:
If your image seems too dark, duplicate the base again (leave it as the second layer, below your soft light layers) and set it to screen, play with the opacity until it looks good.
04. Time to play with curves. I know a lot of people find curves scary but really, they aren't, they are simply another tool for coloring an image. I know nothing about the technicalities of Photoshop and I can use them so you should be able to too. The main thing to understand is that no two images will respond the same way to curves.
The following two images have been colored using the exact same .acv (curves) file (right click, save as if you want to play with this file):
>>>
>>>
Curves are more of an experiment than anything.
So open a new curves layer Layer > New Adjustment Layer >> Curves
The basic idea is that the RGB channel changes the overall color of the image, as well as the brightness and contrast of the image, placing different points on the graph will effect different parts of the image (the lowlights (lower part of the graph), highlights (upper part of the graph) and midtones (middle of the graph)).
The other channels, red, blue and green change the brightness and contrast of that color, as well as it's strength. Dragging the points on the graph to the left of center will make the image more Red, Green or Blue depending on your channel, dragging the points on the graph to the right of center will make the image less red, green or blue but instead will make the image more cyan, magenta or yellow. Again picking different points in the graph will effect different parts of the image.
This is my curves file for this icon, all my curves files for icons like this are variations on this, so download this file and have a play with it. - right click, save as.
To open .acv files save the file to somewhere you'll remember, then open the curves window and click on load.
Don't be afraid to play with this file, move the plots on the graph around until you get something that looks like this:
You want a bright, yellowish effect.
5. Open up a gradient map Layer > New Adjustment Layer >> Gradient Map
This is the gradient I used:
There is no way of saving this as a gradient so instead you can use a similar gradient you already have or you can recreate this gradient by setting your background color to the green shade (#D7EFB9) and your foreground color to the brown shade (#C9BCB7) then selecting the foreground to background gradient, the very first one. After you have your gradient picked click on OK.
You should now have something like this:
Set this layer to saturate, flatten/merge all and your done.
The most important thing is to experiment, try a different gradient or different curves settings and have fun!
More examples:
...
All examples in this tutorial are up for grabs, just credit jaymakesicons.