As a professional we use photoshop pen tool to outline image for remove background which call clipping path. For complex image like hair or far you can use eraser tool or masking technique to remove image background or photoshop extension like knockout or other masking tools also you can use for cutout images.
First I would use a layer filled with a dark or contrasting color of the layer or image I would like to work with. Say if it is a man on the foreground layer, I will use black color as the background layer. The new layer with black color filled is placed behind the layer I would then work with. Now to change the background of a picture, I zoom the picture to nearly 400 times and use the lasso tool to pick what I need. Once the lasso selection is completed, I apply a feather of nearly 5.0 and Invert my selection. One more check to make sure my lasso excludes what I need on the canvas, I hit the Delete button to just have what I need on the canvas. You will be able to see your picture with clarity as the background color gives a good contrast. I will decide on the feather by the way how the delete worked for me. If required one can vary the feather values and hit delete button again. One could also undo what was done earlier change the feather settings and proceed with it again.