How to blur a background
Ever wanted to throw something out of focus in the background but did not know how?
(1) open image in PS
(2) duplicate background image
(3) click Q (= edit in quick mask mode)
(4) choose the gradient tool (make sure reverse is ticked/ and black is the foreground colour)
(5) hold the shift key and click somewhere in the middle of your image; drag the cursor just about 1 inch towards the top of the image (the longer you drag the softer the gradient of the blur will be; you could also just start at the bottom and go all the way up => experiment with this one!)
(6) if you let go – the top of the image should be reddish- if not don’t worry => click: Q again => you should now have a selection at the TOP of the image. If not do the following: click select > inverse
(7) filter > blur > Gaussian blur > try something between 10 and 20 but don’t overdo it!
8. ctrl/cmd + D => deselects
(9) layer > layer mask > reveal all
(10) choose black as foreground colour: now take a soft brush and paint over the parts that you want to have in focus; towards the border of your subject (i.e. hair) lower the opacity of the brush
(and that last part is the trick to keep it realistic! You might need to work around the hair/ face with an opacity of 10%) Take your time with step 10!
(11) you are more or less done- if the effect is too strong- lower the opacity of the blurred layer until happy
Hope this helps?