The Zone System allows you to pre-visualize what the film sees. It's always placing a specific area in a zone and you'll have to figure out where the rest of your scene is going to "fall". You can expand and contract your range, but there's no magic to it. Always expose for shadows then develop for highlights. Take a looksy here.

Ted Forbes is a great photographic educator.
http://theartofphotography.tv/episod...0-zone-system/


This is very useful too.
http://vimeo.com/61485935

Best of luck!