If you can't come up with a way to say something, if your struggling to find the words, I say go with simple. One sentence, just spit it out. Sugar coating, or saying something important in a round about way, beating around the bush it's just a way of making it easier for you to say something difficult. Honest and simple.
If you are ready to come out to everyone else, do that first. I would suggest you tell acquaintances, that is: people who know you but have no emotional investment in your relationship, someone like a teacher you trust, or a friend-of-a-friend you think you can talk to. This practicing has the effect of working out your coming out experiences, of actually hearing yourself say the words to them. Then, as your confidence grows, tell close friends, and siblings (again, people you can trust). Once you have done this, tell the parents, as Stewie suggested above, say it in the first sentence, no sugar-coating, no beating-around-the-bush, so to speak, it is far easier to deal with the questions after telling them. No one here knows how your mother would react, you know her best, so tailor your message to address any fears you can anticipate. But do respond positively and lovingly if she is supportive (do your best to show your appreciation). Typical fears include: your safety (reassure her you will be careful), whether you are sure (tell her you have known for a long time and you would not have told her if you weren't sure), whether it's a phase (tell her no one has truly ever had a "phase" like this while growing up, as above, you are sure), and finally, if there is opposition, do not back down; do not give in, simply agree to disagree and give her the time she needs (as much time as it took you to accept yourself, if need be). Respect her always, even if you disagree, but stand your ground, whether you are gay or not is not an argument you want to get into (simply avoid that discussion), consider it a given, like the colour of your eyes, and bide your time.
Now that I came back and re-read the post, I'm confused. Your mum knows already ? And your trying to tell everyone else ? Or your ready to come out to everyone else but are unsure on how to tell your mom. ?
