Creating a complete fanart graphic/collage (walk-through) :
There are many different styles to do fanart. But in this tutorial, I'm letting you know how to make a nice looking collage with very simple techniques (but long).. using mostly your default tools only.
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1. In a blank canvas, arrange your pictures/images that you'd like to use in your collage like how you want them. I have this start collage. [ LAYER 01 ]
What I did here was pasting the same picture, twice. I rotated one (EDIT/TRANSFORM/ROTATE) and then I MERGE (Ctrl+E) the layers down together.
2. Now next step, I'm going to create a 'negative cut-out' from somewhere in the collage.
Create a new layer [ LAYER 02 ] Use your rectangular selection tool and select an area on the collage, then FLOOD FILL it with a pale/bright/ color. I'm using #E7EEB6. Change the layer mode to either EXCLUSION or DIFFERENCE. depends on what you like best. I also added a 'drop-shadow' style to the layer itself.
To do this, click on this 
on your LAYER PALETTE. And pick DROP SHADOW.
3. Next step i'm going to add another image somewhere.
I took another copy of the same image but in a larger size, and pasted it on the right side of the collage.
As you can see, it now covers the previous effect that we did.
4. I'm going to cut the blank part of this large image so that the image behind it will be visible again.
I also will create a thick outline around the actual image of Jude. I use my magic wand tool. Select/click on the blank part on his right side.
5. Before you do anything else, create a new layer [ LAYER 03 ], still with your magicwand tool selected, RIGHT CLICK on the selected area on the image, and then choose MAKE WORK PATH with a tolerance of 2.0.
Now you have a path surrounding Jude's picture. Now select your brush tool with the path still active, and pick the hard/round brush with size from 3-5.
Pick the color that you want to use for the stroke... then Go to the PATH palette and click STROKE PATH.
6. You will now have a new layer with the outline. but there's a vertical line that you might not want along the middle part of the collage now. just use your eraser or rectangular selection tool and delete the line.
Then you use your magicwand tool again, click on the right side of the outline there.
With it still selected, you move down to your image layer of the large Jude.. then hit DELETE. This will delete the blank part that's covering the previous img.
7. Now you can see your previous image behind the larger image.
8. Because I want to have the larger image to look sharper than the rest, and more smoother, I applied FILTER/SMART BLUR.
Using the blur tool 
, choose a small brush-tip (2-5), I blurred the edgy parts of the skin and his jacket.
Then I applied FILTER/SHARPEN/SHARPEN EDGES for more definition.
Then, I duplicated that layer, and change the mode to SOFTLIGHT.
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