The following images taken by Maurice Collins show the Moon as new(ish), first quarter, full moon and last quarter. The Moon takes about a month to go from new moon through its various phases and back to new moon. Indeed, the word month derives directly from that cycle.
The details on the moon change dramatically from day to day. Indeed even from hour to hour the change in details can be facinating with some features only observable for a few hours at the right phase. Binoculars or a small telescope are fine as a starting point for observing the Moon.
The first image shows the evolution of the moon's phase at about two day intervals during April 2009.