When you have a really big scene with hundreds (or thousands!) of objects, it can be difficult to work with specific little things. Fortunately, Blender allows you, with a single keystroke, to hide everything except the current object so you can manage individual objects inside crowded scenes. This is called "isolation", and in technical Blender terms: Global or Local View. Let's see how it works:
- Select the object you want to focus on.
- Hit / (slash) in the NumPad (or the Global/Local View option in the View menu of the 3D View header).
- Now you'll only see the object you need to see. Keep in mind you can't do certain commands while in Local View. At the top left corner of the 3D View there will be an indication if you're in Local View.
- Once you're done, hit slash again in your NumPad, and you'll see again the whole scene.