Duncan Holmes , Nov 22, 2010; 07:12 a.m.
Cloudy means nice even lighting, remember that bright sunliught equals harsh shadows. If it is really dull and there's just not enough light, then you will need to play with fill flash without making them look like cardboard standees). If you drop the flash below 1 stop you should get catchlights in the eyes without overdoing it....some experimentation is needed. Rear curtain flash can help to capture more of the environment on slightly longer exposures than you might otherwise do.
Autumn winter means there's lots of leaf litter and other stuff (looking down and around) that can add to the composition. Looking up at the dull sky you might only get bare branches in silhouette which isn't as enticing a view for family pics.