Select the Crop tool and immediately you’ll notice a difference. There are grabbable handles at the corners and sides of your image, which can be quickly and accurately dragged to where you want to crop. You can also view a choice of overlaid guides based on traditional compositional concepts from the Rule of Thirds to the Golden Ratio.
If you want to constrain your crop, a drop-down menu in the Options bar gives you a choice of aspect ratios including square, 4: 3 and 16:9 – and you can create your own.
Hit the tick button to apply. If you turn off Delete Cropped Pixels in the Options bar, Photoshop keeps the trimmed areas as part of the document in case you want to bring them back in later.