
Please note: I'm writing this from the perspective of a woman looking for her first job while transitioning, though most of it applies, mutatis mutandis, to trans-men and those transgendered who want to work in their target gender.
Getting that first job in your target gender is a wonderful feeling
What a relief! It's important not just because it affirms who you are, or because you have to eat, but also because living on what is, for you, the wrong side of the gender divide, is stressful; trying to live on both sides at the same time is complicated, fraught with problems, expensive, and will just sap the energy right out of you.
Be prepared to accept a different type of job and lower pay.
Being a receptionist, secretary, or office manager might not be the same in terms of either prestige or money, but it provides something that many jobs don't - public validation of you as a woman. Also, because there's less competition for these traditional "pink collar" jobs, and the money in play is less, the screening process is a lot less rigid. Can you use a computer, answer phones, take messages, and file? Then you have a good chance of landing that important "first job."
Why a "pink collar job"
First, why not? It's honest work. Second, often it's a woman doing the hiring, and I've found that women are much more helpful. It might sound like a sterotype, but you'll find there really is a "sisterhood", just like you'll find that men are often more interested in looking at your boobs or legs than your other qualifications.
Also, you might want to do this because you want a clean break from your current job. Your co-workers, no matter how well-intentioned, will remember the "old you". There's nothing worse than someone accidentally (or, worse, on purpose) calling you by your old name in front of someone who doesn't know ... and it just spreads. Even if nobody slips up, new hires and outsiders will wonder why, every time an issue arises about work done by "the old you", it's referred to "the new you".
And then there's that stupid "which bathroom" issue. At a new place, chances are nobody is going to make a fuss, since they don't associate you with your previous gender. Being able to use the women's washroom without worry is worth a pay cut.