Use Photoshop's Background Eraser Tool.
If you find yourself needing to quickly remove the background from an image in Photoshop, take a moment to play with the background eraser tool. (Click-and-hold on the eraser in Photoshop's tool pallet to choose this tool).
The background eraser samples the color in the center of the brush. It deletes that color and softens the edges so that color halos are not visible if the foreground object is later pasted into another image.
We've recorded a short two-minute video tutorial demonstrating this technique in action:
Source: This tip originally appeared in QuickTips #61 a year ago this month. It was mentioned specifically by one of our newest new email subscribers. The original tip was inspired by a quick Photoshop coaching session with Robin Pederson, in-house graphic designer at MultiCare. Photo from Ed Lowe Photography.