Oh, I had misunderstood. Looks like you're quite intent on transitioning already. In that case, uhm... Well, uhm... If you're confident enough, try going out 100 % female sometime. I haven't done that yet, but it's supposed to give you a big confidence boost.
Also, working on your voice could be good. My voice is supposedly really feminine, and I never use any but it, but I still "pass" as a weird male for now (except security checks on the phone, but that's another story). There are men with feminine voices, you know. A co-worker of my mother's had that, as well as an androgynous name, and he ended up changing his name to a really male one to make sure he wasn't called madam on the phone, hehe. And no one questions his masculinity.
Also, think of the phenomenon called "metrosexuals", men who take care of their bodies much like women do. Apart from "hurr hairy truck driver alpha male" men, no one calls them any less male for epilating and using moisturisers and foundation and stuff.
You can also start facial hair removal. If you need to, you can use an excuse. "I get too many ingrowns; it's a real issue." "I'm really tired of having to shave every damned morning, and heck, I don't intend on growing a beard, so why not?" "My skin is just too sensitive; all razors just destroy it." There are "real" men who get their beard lasered, after all.
And you can buy a few women's androgynous-looking pieces of clothes, again with an excuse if you need it. For the clerk, you can be buying it for your twin sister, who pretty much has the same sizes as you, so you're trying them on to make sure it fits. Or you could complain about how much you have a girl's butt and always have to buy damned girl's jeans because nothing fits you, even if it's not really true. Or you can say that your feet are too short for men's socks. Or you could be doing a short film for an important school project, and need a realistic cross-gender outfit, and complain about how they picked you to be the pretty girl 'cause of your long hair. Excuses are useful when you lack confidence.
But in the end, you will have to come out. I personally don't believe so much in not caring about what others think. Of course, I'm all for being yourself and not conforming too much, but unless you want to create difficulties for yourself, you sort of have to "help them accept you" a little. So going gradually and not "BANG; today, I'm myself! Screw you all and your opinions!" which is likely to cause shock for everyone including you, and might actually appear as mental instability, is probably a better choice.
For example, slowly feminise your appearance and behaviours whilst letting others accept that you're a weird, effeminate person. If, after a while and they seem to have accepted you (and most should, really), if you come out to them, it'll feel like less of a "You lied to us!" or "What the heck? ->-bleeped-<-!" and more of a "Oh, THAT's what was up! So he, uhm, she, can be herself now!" It's not magical, but I think it should really attenuate the shock of coming out for both you and your peers.
And as soon as you're sure that you're transsexual and are going to transition, if you aren't already, you will need to come out to your family. They deserve to know, right? They're close to you, after all. And if you wait too much, they might feel betrayed. Even if they're religious fanatics with torches, you don't depend on them for living, right? You have a job, after all.
But in a more normal case, if you sort of use the same method with them, and do the coming out with tact and understanding, and explain everything to them to the best of your ability, and don't confront them, but rather accompany them into understanding you, it should go fine. They might not understand fully at first, but they should accept, at the very least, and try to understand their best. I think they might actually see it as a little relieving to finally understand "what's wrong with you". Because don't underestimate family. They probably noticed something. My mother and sister, at least, already "knew".
And all that will be much easier to do if you have a therapist who accompanies you instead of challenging you. Plus, if you're still not 100 % sure, they're (theoretically; not sure what happened with the first one) good at helping you figure everything out. I hope your new therapist is nice.
