Here’s a nice tip discovered by a MacRumors forum member.
You can drag around the Spotlight window in El Capitan. This is a well known new feature.
What’s not well known is that by clicking and holding the Spotlight icon at the top right of the menu bar while the recently-moved-around Spotlight window is open, you’ll automatically recenter and resize it on the screen. In fact, it’ll switch back to default size and positioning.