QuickMaskMode (Press Q) , color subject accurately within intended glow, right click to select appropriate brush, exit QuickMaskMode (Q), Selection>Inverse, (Optional: Select> Feather), Ctrl-C or X then paste(CTRL V) and play with the Blending Options(right Click on Layer)..
Typically OuterGlow & Inner Glow
I dunno how the pros do it, this is how i achieve the effect.. can also use it to blur the background, or any effects that u wanna isolate from the other layer.