Yesterday I mentioned that discipline really isn't about saying "no," it is about saying "yes." Yes to our mission/values and No to other things.
However, this is a bit incomplete. There are many situations where other people are expecting us to say "yes" to them, but we would rather say yes to something else. This means we actually have to deliver a "No" to someone.
The problem is, there are a lot of activities that contribute to our mission/goals. The ability to prioritize tasks is important. What kind of tasks am I talking about?
Let's reference the 4 Quadrants mentioned in Habit 3.

What is the optimal ratio of time spent on each quadrant? As Covey explains...
Some people are literally beaten up by problems all day every day. The only relief they have is in escaping to the not important, not urgent activities of Q4. 90 percent of their time is spent in Q1 and the majority of the rest is Q4. The results?
Stress
Burnout
Crisis Management
Always putting out fires.
Other people spend their time in Q3, thinking they're in Q1. They spend most of their time reacting to things that are urgent, assuming they are also important. Results?
Short-term focus
Reputation - chameleon character
Feel victimized, out of control
People who spend time almost exclusively in Q3 & Q4 basically lead irresponsible lives. Results?
Total irresponsibility
Fired from jobs
Dependent on others or institutions for basics.
Effective people stay out of Q3 and Q4 because, urgent or not, they aren't important. They also shrink Q1 down to size by spending more time in Q2. Results?
Vision, perspective
Balance
Discipline
Quadrant 2 is the heart of effective personal management.
So if we’re going to say "Yes" to Q2, we need to be able to say "No" to the other quadrants. This isn't always easy, of course. Q1 deals with crises, after all. It is not very reasonable to expect that we can say “no” to Q1 when those activities come up.
The first step, as Covey suggests, is to begin taking from Q3 and Q4. This is where the "burning yes!" from yesterday comes into play. To say "No" to the simple pleasures/escapes in life, we must have an internalized mission calling to us.
The beauty of starting with Q3 and Q4 is that Q1 will begin to shrink, on its own, over time. As more and more time becomes placed in the proactive zone of Q2 less and less time will need to be spent on crises and problem-solving.
Let's look again at Q2 activities:
Relationship building
Finding new opportunities
Long-term planning
Preventive activities
Personal Growth
Recreation
Each of these tasks contribute, in their own way, to reducing the size of Q1.
But again, I must press the importance of having a strong mission, a "burning yes!" to help drive you. If you are centered around anything other than sound principles/values (like spouse, money, friend, self, etc.) you will find yourself thrown "back into Q1 & Q3, reacting to the impulse of the moment. "
So what does it take to say no? Further exploration of discipline and prioritizing time.
The basic problem is that their priorities have not become deeply planted in their hearts and minds. They haven't internalized Habit 2.