Once you've decided that you're absolutely sure you'll quit your job, you should make a bullet-proof game plan so you don't get left in the lurch after you quit your job. Ideally, you should quit your job only after you've found another job because it'll be harder to find another job as an unemployed candidate.  Don't assume that you can just "make it work" until you find another job. In today's economy, you might be unemployed longer than you imagined. Don't quit your job in the heat of the moment and just assume that you can figure it out after the fact. Line up another job before leaving. You should spend some time on the job market as you try to leave your current job. You shouldn't be dishonest about the fact that you currently have a job when you speak to potential employers. If you don't have another job lined up, make sure you have enough money to be unemployed. If you really can't stand your job, tap into a savings account so that you can leave earlier. This means that you will have to budget until you can find another job. When saving up, plan for an extended period of being unemployed just to be safe. When you do leave your job, make sure you're doing it for the right reasons. Don't just quit because you feel undervalued or underpaid before having a conversation with your employer about it first. If you don't try to solve the problems at your current job to the best of your ability, then you may face the same problems at your new job. . This is the respectful thing to do. Remember that the company is relying on you and will have to fill a hole as soon as you leave. If the company has a policy for having to give notice earlier than two weeks, then respect that policy.  Even if the company doesn't have a policy of giving more than two weeks company, if you're one of four employees at a company, use your judgment to determine how much time the company would need to fill your shoes. Make sure you're financially solvent and prepared to be out of work for the next two weeks in the event that your boss or...

TL;DR in Vietnamese:
Lên kế hoạch những việc bạn sẽ làm sau khi nghỉ việc. Hãy thông báo trước hai tuần. Thông báo với cấp trên. Chuẩn bị trả lời câu hỏi của cấp trên. Soạn một lá thư từ chức lịch sự. Vẫn giữ sự chuyên nghiệp sau khi đã thông báo với cấp trên. Một khi thời gian ở công ty của bạn đã hết, hãy rời đi theo cách lịch sự và thân thiện.