But wherever there is freedom, there must be responsibility.  this brings us to the 4th principle of mental conduct.

Have a Purpose and a Quality Purpose:
Now we know the law:  what we think, we create.  The 4th principle tells us how to use our power responsibly in invoking this law.
First, lets talk about the most basic part of this principle:  have a purpose and determination.

Be Specific: 
When you decide to make a change, achieve a goal, or create something new in your life, you must focus your objective clearly in your mind.  the thought form, “I desire a change in my social life” will take form somehow, but it may be so vague and indistinct that you won’t notice a change.  ” I desire to meet more people” is better; “I desire to meet more people who share my interest in flying airplanes (or whatever)” is better still.  Focus as specifically as possible on what you want to accomplish.  When you want to buy a car, you identify the make, model, color, and accessories that you desire.  When you take a vacation, you plan exactly where you want to go, where you will stay, how you will get there, and proceed to make all the proper arrangements.  You are being specific, aren’t you?  The great goals in your life deserve as much care, don’t they?  Be specific!

Then, focus your will and unflinching determination behind your purpose.

by Dr. Tae Yun Kim (page 31)