If you give your objects and groups names They can be identified and selected easier. by using the tools and options Ang25 shows. They can also be selected by holding the Ctrl key and clicking on the objects. A pop-up menu will appear with a list of all objects and groups located were the cursor was Ctrl clicked.

Two other features that help work flow in clustered scenes are:

1. The family tools,
2. Solo mode

Example of families: say you have many objects that share the same material. You can put them all in the same family, then if the material needs to be changed or tweaked they can all be easily selected using the family menu.
Solo Mode: Once a group or objects have been selected, you can go into solo mode to temporally hide all the other object.
A good example of using solo mode is, say you have a full scene, and you need to import a new model that contains many parts. You can go into solo mode ( with no objects selected even before you import it. Then when it's imported it will be the only model seen and listed on all the selection menus. All the different part are easier to select to place materials on. After the editing is done to the model you go out of solo mode to place and do other translations to it.

Stephen Ray