Select your subject
Go to the Toolbox and click on the Quick Selection Tool. Draw over your white background to select it and keep brushing over the white areas until they’re all selected. Use the [ and ] keys to resize your brush accordingly, and if you need to remove an area from your selection, hold down the Alt key and then brush over the offending area to remove it. When you’ve got all of the white background you need to tidy up the selection. To do this, go to Select>Refine Edge and set the Feather to 1px. Using the Refine Radius Tool from the Refine Edge panel, you can brush over all of the flyaway hairs to add them to your selection. When you’ve got all of the hairs, hit the OK button.