I was given some excellent advice by an older transwoman when I told her I was trying to pass, having just gone to living 24-7 as a woman a few months earlier. “Don’t” she said. “By trying to pass you only make yourself more nervous and will be more likely read by anyone you meet.
Now here at transadvocate.com is an excellent article on the perils of passing, and the difficult history of the term. I can also recommend the book “Nobody Passes“, an anthology of genderqueer perspectives.