Turn on the Selection Pane
On the Home menu, far right:
Click Select | Selection Pane
The above is an example, it's from a slide I made where I had a number of different objects. I have renamed my objects so they make sense to me. You can do the same.
Opposite each object in the list is a little icon, an eye. The 'eye' is a switch, click to hide or show the object. For example, if things are really busy on your slide, click Hide All. Then click to show (un-hide) the object you wish to work on.
When you are finished click Show All.
It's a bit like layers in Adobe products. The Selection Pane is a life-saver!
I am using Excel 2013 but I'm pretty sure this feature was available in 2010 and even 2007. Maybe someone can confirm in the comments below, thanks! :-)