I am having & always have had a problem w/ attaching an xref w/ AutoCad 2010, the xref is very difficult to see. Is there any command or setting that will enhance the xref so its more visible and/or much less dark?

In Options (Preferences) there is a setting called "Fade control" on the "Display" tab.  Move the slider under "Xref display" to change the visibility.

Alternately, you can use xdwgfadectl command. Its value range is -90 to 90. -90 is for normal visibility and as you increases the value, it starts fading. 90 is for least visible xref.