Have a serious talk with yourself. Clarify specifically what you hope will happen as a result of disclosure, what you expect will really happen. Without a clear purpose, your presentation of self may be a scary and risky experience without an attainable objective.
Select the particular person or persons to whom you wish to disclose. Tell the person(s) that you want to share something important, that you want to have a serious personal conversation. Although you cannot make someone ready to hear what you have to say, you can create a situation in which the other person feels ready for a serious personal conversation.
Select a time and a place. Avoid situations which may result in a lack of time or privacy. Neither you nor the other person can interact honestly and fully if he/she does not feel there is enough situational privacy. Coming out is a continuing process, not a hit and run bombing mission or something done well in a crowded public place.
Keep your disclosure clean. That is, don't clutter it up with attempts to punish, cause guilt or gain sympathy. Talk about yourself, your feelings and your experiences. Stay with "I" statements. Being gay is no one's fault. What you as a person decide to do with your gayness is your responsibility.
Allow time for surprise reactions. It is doubtful that you came into self-acceptance overnight. Asking that another accept and appreciate you faster than you have learned to appreciate yourself is self-defeating.
Be ready to clearly identify learning resources which are available to the person. For example, books, films, magazine articles, journals, counselors etc. As your learning has taken time and energy, the "significant other" will need time to digest your disclosure and ingest a new understanding.
An important step, certainly not the last priority, is the setting up of a gay support system. Participating in a gay, lesbian, bisexual support group can help prepare you for disclosure to significant others in your life. It can also provide you with support and understanding during and after the disclosure. If this type of group is not available to you, having supportive friends, teachers, relatives, etc. is also a good source of support for the coming out process.