You can set many of AutoCAD's display elements to your personal preferences. For example, the size of the crosshairs can range from 1% to 100% of your screen size (at 100%, you don't see the ends of the crosshairs). This is set by the CURSORSIZE variable; the default is 5. Also, you can change the size of the pickbox -- the little square at the intersection of the crosshairs, and the box that shows up at the "select objects" prompt. This controls how close you have to get to something before you can select it. The variable for this is PICKBOX -- it can be any integer 0-50, and defaults to 3.