Has someone ever said to you that the best time to take someones photo outside is when its bright and sunny? Well I could not disagree more, I find the best time to photograph outside is during an overcast day.
The reason I like shooting during overcast days is because the clouds act like a huge softbox. They soften the light form the sun so that its nice and even on your subjects face. It knocks out all of the shadows that would be there if the sun was out and not being diffused.
Here are some tips for shooting during overcast days. You may have to bump your ISO because the light is being diffused by the clouds. When the light is diffused that means there is less light hitting the subject thus why we would want to bump our ISO to compensate.
If it is not an overcast day and you need to shoot outside look for areas in the shade such as under a tree or next to a building. This way you are shooting with less harsh light which tends to cause ugly shadows.