The trick i've learnt with editing is to be brutal, then look back at your edit a few days later, and be even more so. It's always painfull to have to cut bits out, but many times have I looked at one of my 'finished' videos a few days later, only to spot more bits that could do with being given the chop.

Also in my experience, ignoring the director can help occassionaly. They may well have an idea of what they want, but that's not a garantee that they're right. I've produced a handfull of edits of the same promo for one company, each of them their own ideas. Yet the only one they were happy with was the one I did my own way. They even thanked me for it in writting