The key to a good fade is not talking about your doubts, not acting disgruntled, and not openly adopting some other belief system (religious, political, spiritual, philosophy, or conspiratorial).
Whether you're fading fast or slow, just always smile, be positive, and act excited to see every JW you see while hinting at (but not directly stating) you're dealing with depression or health problems.
Whatever you do, never say anything negative about the organization, the elders, the GB, any other Witness, or your own personal experiences.
Remember the Miranda Rights, "You have the right to remain silent, anything you say can and will be used against you..."
Don't give them any weapons to use against you & they will lose interest.