borders

hmmm...well, to do a lazy ass border, I just extend the canvas size in PS and fill with a color. To do a simple inset border, I use the shape tool and set it to rectangle, then draw out my rectangle. Then I switch to subtract from the area and cut out the inner part of the rectangle. I usually make this white and then make the layer a transparency of like 15-20%. If you rasterize the layer, you can add special effects to it and stuff. For fancier stuff, I'll use a special brush, but I keep most of my borders pretty simple since my personal style is a bit more clean and streamlined.

fill selection, contract selection by some pixels, delete selection

I do it on a separate layer on top of the background layer using the square selection tool. Just select a square about 10 pixels in from the edge, if you want a border from there to the edge, right click within the selection and pick select inverse. You can stroke with any color. Then use blending options to make it different.