The steps to do this include:

1. Select the crop tool.
2. Click down and drag to create a rectangular shape around what you want to keep in your final image.
3. Double click inside your selection to accept the crop (or select another tool and click ‘crop’ from the pop-up dialog box that appears).

====OR====

1. Select the crop tool.
2. Grab one of the handles that appears around the border of your image.
3. Click down and drag in. Repeat for all edges you want to modify.
4. Double click inside your selection to accept the crop (or select another tool and click ‘crop’ from the pop-up dialog box that appears).

For best results, I encourage you to watch the short quick tip video above as many times as you need!