In most cases, you can hide a number of your object through the outliner however a quicker way in Blender 2.8 is listed in the step below.

1. Make sure you are in wireframe, shading or Eevee viewport shading mode. (Currently, isolate object does not work in Cycles preview mode)2. Select the objects you want to focus on working.

3. Press / in the Numpad area. This will quickly hide everything unselected.

4. To toggle back press the / again and this will unhide the objects you had isolated.

This Blender Guide on Design Sync [...]