The only advice I can give is: forget the boundaries and be, wear, feel... what you really want.
First of all, we've been always taught a set of norms of gender and some social irrational behaviors, just don't let them limit your view of the world, don't let them limit you.
Secondly, I don't really know who I am either, but I can tell you that one of the things which are helping me the most is experimenting with my gender expression in my inner social circle. I started only a few weeks ago wearing female clothes and asking to be called by the corresponding pronouns, and these real interactions have helped more than months of thinking! Also, this forum is helping a lot.
About the clothes, I started with leggings, which are more "socially accepted" for their use in people read male than other female clothes, and these are good new if you have concerns about this as I had. Skirts are comfortable too in my opinion.