start learning to apply cosmetics. The sooner, the better. The drug store stuff is fine to learn with....but eventually you'll want good stuff so it will last all day.
Work on your voice. It took me about a year to have not only a good passing speaking voice...but also to have female sounding sneezes, coughs...and of course bedroom sounds

Find a female singer that you admire, and SING it loud in the car while driving around.
Work on body language (although a lot of this will come naturally once the E starts flowing....did for me anyway). Learn to sit with your legs together, for example...and how to walk in heels.
There is soooo much you can do while waiting for HRT....but I totally feel for you....that period was Hell for me, and I was much like you...totally obsessed, and wanting to get the ball rolling already!