Scheduling is a delicate art that balances current workload, internal resources, client expectations and occasionally something we have come to refer to as "reality."
But only occasionally.
Creating a reasonable and achievable timeline, based on all knowns and suspected unknowns (contingency planning) is a skill that's learned over time.
Clearly written site goals and descriptions; detailed navigation charts; look/feel/features documents can be seen as an essential insurance policy against wasted time and costly miscommunication.
The Project Manager is partially responsible for the mood of the crew. Team members want to do a good job and deserve recognition for a job well done. The Project Manager should be aware when extra effort will be called for and when it has been put forth.
Technologies change rapidly--people remain essentially the same. In an intensely collaborative medium such as website design and construction, teamwork is key. The essence of teamwork is having respect for and valuing everyone's contribution to the final product.