I'm new to SolidWorks, and just need some advice. 

For starters, is there a way to change driven dimensions?  I've been trying to find a way to change them with no success, am I just missing something glaringly obvious?  Secondly, is there any advice/rules of thumb I should follow that will make things simpler?  I'm used to CAD so the transition is strange for me.

Thanks in advance for anything you tell me!