If you select two or more objects in the layout editor, and then choose 
(preferences) from the Layouts menu you will see a rather imposing dialog with the title Set Attributes of Selected Items. This dialog is the union of all of the attribute editing dialogs that are available for editing arrows, boxes, graphs and text objects.
The advantage of this window is that you can use it to set the appearance of many items at the same time. If you have dozens of graphs in a layout, and want them all to display axes in a larger font, you can select them all and choose Get Info…
Click on any of the sections of the dialog box below to jump to the page which describes those features. You also may want to look at the pages giving an overview of the Layout Editor, the controls in the Layout window, or more about grids.