Resignation letters are as important as application letters if not more. Remember, the last impression must leave a lasting impression. It is important to write the resignation letter in a polite and courteous tone, whatever maybe the reasons for your resigning. You must keep in mind that resignation letters are considered as official documents and will continue to be in the personnel files of the organization you are leaving.
It is a formal letter and should be written in the suitable format. Make sure to reiterate facts like the post from which you are resigning and the effective date of your release. It is also imperative to give genuine and valid reasons for leaving a job.
It is a good time to thank the organization, peers and superiors for the work-experience and overall growth you have garnered. This gesture helps you leave with good will and can stand you in good stead when you are looking for a reference letter.
Though resignation letters are generally the last official communication you have with the organization, it is important not to burn any bridges.