Zooming in, zooming out, zooming in...

Save yourself the headache of constantly zooming in to work on detail and then having to zoom out again to get an overview of the whole image.

Go to Window and make a New Window. This will give you a second view of the same document.
Make one of the windows zoomed in to work in detail and the second one zoomed out to work at a distance.

The clever thing is now to learn the keyboard shortcut to switch between the two.

Hold the cmd and tilde key, which looks like this.

You can then quickly move back and forth between the two with the shortcut and any changes to the drawing you make in one will be changed in the other. Nice.