Instead of hitting option-command-=/- to zoom in/out, hold the ctrl key and use 2 fingers on the trackpad or alternately, scroll on the scroll wheel to zoom in/out. Much faster, much easier.
Note: Only works with 10.4 and above. Also required is a trackpad with the scrolling feature (~2005+, you can check this by seeing if your laptop has built in bluetooth. If it does, you’re good to go), or a mouse with scroll wheel/ball.
Also see this past article on the zooming feature