Having lots fo natural light is a huge bonus. I would recommend treating yourself to a reflector to start with .... something like this
NEW 5 in 1 Collapsible Circular Reflector 110cm 43" UK on eBay, also, Studio Equipment Lighting, Photography (end time 07-Jul-08 11:17:26 BST)
This will allow you to bounce light back in to the shadows & the other advantage is a reflector cannot bounce more light than is present, so you always end up with a natural looking shot.
These shots are taken with window light only.

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