It is now easier to see the edge of the crop with new handles. They appear in the corners and the sides of the crop, making it easier to grab and resize the crop.
New modifier keys have been introduced, allowing cropping around the center with the Alt key and locking the current aspect ratio with the Shift key. Additionally, freehand rotation can be accessed by either moving the cursor outside the corner of the crop or by using the modifier key Cmd/Ctrl (macOS/Windows).
Hitting the Enter/Return key while using the Crop tool will now switch to the Pan Cursor tool and show the image in its cropped state.
Watch this tutorial explaining how to use the Crop tool.