Now this seems like an interesting, perhaps weird title for an article, but it highlights what a TransGirl faces as she faces the vast amount of socialization and medical issues that await. Cisgender girls learn this gradually from friends, magazines, mother, etc as they "transition" through puberty. A TransGirl is on a crash course learning the same material plus what to do with their current social relationships and medical issues. As Kermit the Frog said, "It isn't easy being green", but green we are and there is no avoiding it. So how to approach the subject?
Many have suggested this as a first step, "Study the subject", that is, watch girls who fit your age group and life style. Adopt behaviors that seem successful, YouTube is marvelous--just search for the topic of interest, it's all there. Let's pick one, eye makeup. Even this isn't simple, so break it down into components, eyeliner, eye brows, shadow, etc. Each has variations.
Then there is hair. Look at various styles. Some magazines address this endlessly and of course there is much on YouTube. And clothes, walking, body language, physical expression, and last, but certainty not least, voice--the most difficult of all.
There is the bathroom... There are social customs and they are different for each gender, that is, men and women. If you don't adopt the appropriate behaviors and appearance you won't be accepted. There are many internet articles to be studied before you commence "field trials".
I read several biographical articles and books by others describing their experiences and questions as they challenged this gauntlet of adaption and mimicry. Mimicry...definitely!!! If it looks like a duck, walks like a duck and quacks like a duck, it is a duck and people vote your gender based on a predominance of factors they associate with each gender presentation. Do a search on Amazon to find books that will help you.
So, I have opened Pandora's Box and many challenges await, but if you are transgendered there is really little other choice but to become a dedicated student of your gender's characteristics.