Ok so ive seen so much bad rendering, so im making a guide.
Stage 1:
Ok for newbs to use:
Magic wand or quick selection tool.
So lets start using it,
First get a clear easy image,
Now get that quick selection/magic wand.
Drag your mouse around areas to select it or hold shift and click areas.
Now delete your destruction.
Now no matter what go to Layer/Matting/Defringe.
It will make it nice.
Stage 2:
Ok for middlestaged:
Lasso tool/Eraser
So lets start to use it,
First get a Fair normal image,
Now get the Lasso/Eraser.
Erase some hard parts which arent lassoed or,
Have a steady hand and lasso good!
Now delete it.
Go Layer/Matting/Defringe
All clear
Also Note that you can use the feather way(Look at bottom)
Now for Pictures

Coming soon)(Friday)
Feather way:
Select your Background around the render and Right click/Go Feather
Also for Tip Of The Day
Always focus on your depth.Or it is'nt a signature.