To select objects hidden behind other objects or simply below a larger object, Command + Click until the object you want is selected. Each click selects the object below the previous top object. When you reach the object you want, you can move the object by dragging it while the mouse button is still held down, or drag it from the object’s center point. This is a handy tip, but I’ve found it easier, and more beneficial to make heavy use of Layers. I put text on one layer, borders on another, photos on yet another… it makes it MUCH easier to change things later if I need to.