I set the Fn button on top of the camera to magnify the view (two click the first time you use it, one click the next times), and back to full view at the press of the shutter button, unless I'm using really long lenses: in those cases I prefer to set the camera to use the same Fn button to go back to full view, so I can focus using the magnified view with the shutter button half-pressed, and the image stabilized (to do this you must set the IS to be active at the shutter half-press ).
I hope you can understand my poor English ;-)