When it comes to make your viewers to focus on a definite part of a photo then apart from making other part blur or darken it, the most common method is to crop the image. Definitely cropping is one of the most used method to define your center of attraction in your photo. A bad crop or no crop can ruin your photo while a good crop gives more perfection to your photo. Thank god, we have tool called as Crop Tool in Photoshop to crop images.
Crop Tool in Photoshop
To select crop tool all you need is to press Shift+C again and again until it comes. You can also select it from the tool panel (left one).