Venus is actually best observed in its crescent phases during the daytime, assuming you're experienced enough to know how to find the damn thing. Not often easy. You usually need to find an obstacle such as a building or a tree to block out the nearby sun. It appears in its crescent phases when its near the sun in the sky. That is because that is the time of its orbit when its bringing its dark side around to face us and we see less and less of its bright, sun-facing side. It's best to see during the daytime because its much less bright at that time. You can much more easily make out the crescent shape when its comparatively faint in the sky. Otherwise all you see is a super bright glaring light.
Re: It appears in its crescent phases when its near the sun in the sky. That is because that is the time of its orbit when its bringing its dark side around to face us and we see less and less of its bright, sun-facing side
That is, this is when Venus is preparing to come between Earth and the Sun in its orbit round the Sun, or when its emerging from behind the Sun.