Without makeup and without a wig, it's pretty unlikely that you'll pass. 95% of people can't pull that off, and maybe 4% can pass as androgynous. I'd suggest you hit a few of the stickies and maybe the MtF Makeup thread I've seen around.
On that note, or maybe it's completely unrelated, I should post one of myself at some point.
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COSPLAYS IN PROGRESS
Utatane Piko - default (Vocaloid) - 90%
Connie (Shingeki no Kyojin) - 0%
Sheik (OoT/SSBB) - 53%