Unfortunately, every company doesn't need or deserve to be there. You should have realistic expectations of what PR and advertising can do, and work with the agency to set mutually agreed upon goals and objectives that are attainable and measurable. For example, we recently launched a recruitment advertising campaign and set a goal with the agency to have it drive a specific number of recruits through our HR department. We agreed on the number together, based on the type and amount of media we were going to use. We hit our goal because everyone had clear expectations about how much work the advertising had to do.
Nothing kills an agency's spunk more than indecision and procrastination.
No one has time for marketing until it gets blamed for all the company's problems. Participate in the process early and often, and give it quality time. Remember, garbage in, garbage out. You do a lot at your company to attract and retain good people. Use some of those techniques on your agency.