For individual attractions with lines, I always use the rule to go to the left line if available as most people mindlessly veer to the right. As far as the parks themselves, I bypass everything (probably wasting much time) and head straight to the attraction that I absolutely MUST DO or my vacation will be a disaster. Once I've satisfied that need, I just plan strategy from there. (MK=beeline to Space Mountain, DHS=beeline to Tower of Terror, EPCOT=beeline to Soarin' AK=Eh...not my one of my favorite Disney places). As a rule, though after I complete my obsession attractions, I usually travel counterclockwise.