Here’s a Photoshop shortcut for moving a Marquee selection as it is being drawn…
It’s a nuisance when a Marquee selection has been made but it’s not quite in the right position. It can soon turn into guesswork.
The trick is not to let go of the left mouse button when drawing on your selection, just hold down Spacebar and you can drag the selection.
Once it’s in position, let go of Spacebar and continue to resize its area, still holding down the left mouse button.