Leaving a long-held, cherished job is not easy. To quit, follow the steps below in order and as precisely as you possibly can. Make sure first, though, that you have really decided to quit and that it is not just a ploy to get your employer to talk you in to staying and giving you a raise.
1. Remember that you need to be loyal first to yourself, not to your employer or your colleagues no matter how much they have done for you up to now. Almost everyone thinks their own departure will be more catastrophic for their organization, its employees, and its customers than it will really be.
2. Come up with three iron-clad reasons that explain why you have decided to quit. Any more than three leaves you open to having the weakest refuted allowing your employer to claw their way back to convincing you to stay, and their instinct will be to try to talk you into doing exactly that. Memorize your three reasons and become glib with them.
3. Say out-loud that you are leaving and why, over and over again, in front of a mirror so you will have heard and felt yourself speak the words in a safe and unemotional setting.
4. A day or so ahead of announcing, do something to manifest your decision to leave; for example, exercise and sell all of your vested stock options, take your favorite knickknacks out of the office, give up your parking space, or something along these lines to convince yourself and to show colleagues and management that you really have checked out.
5. Set up a time to speak with your manager; ideally in-person but electronically if it is the only option. Draft your resignation letter that says:
a. You resign as of a specific date to pursue a specific other opportunity.
b. You have strong positive feelings for your time at the organization.
c. You are committed to do all you can to orchestrate a smooth transition.
6. At the start of your meeting, hand over the signed letter and allow time for your manager to read and absorb its contents. Offer to talk through the three reasons why you are quitting and explain what you have already done to mentally and physically check-out. When s/he attacks your reasons for leaving it is important to say exactly this: “I appreciate you helping me to rethink my decision but it is my decision to leave”.
What will follow is a gradual progression through a series of predictable stages of acceptance: shock, denial, pain, anger, bargaining, depression, and finally acceptance. Stay calm and help orchestrate the progression through the stages until acceptance is reached.
Excerpted from one of my post popular and useful posts ever is on how to quit a job.