The first thing to remember is that everyone is trying to pass as something - cool, good-looking, funny, intelligent, suave etc. Your journey includes any of these plus a change in gender. Easy? Not really, but it isn't impossible either.
Walking:
Watch how men walk and practice at home. Try to relax and do everything you were told not to when you were younger. Men are sloppy creatures so anything that is less than perfect will probably work … feel free to take up space - be purposeful and sure of yourself. On the other hand, avoid the primate walk - any man looks unattractive lurching down the street like an escaped extra from Planet of the Apes. All you want to do is pass and in many ways, less is more - anything less than walking like a woman will get you through. The best advice I can think of is not to try too hard.
Standing:
Distribute your weight evenly on both feet - stand as if you are in front of a urinal - feet shoulder width apart (which is a lot less than people often assume) and stand tall. Don't let your hips slide sideways, stand with your knees together or look as though you are trying to slip into the background. You don't have to make a big statement, just look confident and sure of yourself.
Handshakes:
Check where the other guy's hand is (quickly - don't stare at the hand) and grasp it
firmly - you probably won't win any strength competitions so just make it solid and
firm. Lock your thumb into the other person's hand and shake - no excessive evangelical preacher/ used car salesman pumping. Look the other person in the eye and
stay calm - it will be over in a couple of seconds and after a while it feels
completely natural. Avoid dead fish handshakes at all costs.
Speaking:
Try to eliminate any upward inflections at the end of your sentences. Practice
keeping your voice steady and almost to a monotone. Use a reasonable volume as
men speak louder than women: if you speak too quietly people will see you as lacking
confidence. Men interrupt more often so once you feel confident you can jump into
conversations fairly readily. Then again, knowing what you know from your previous
life it could be a good move to integrate both aspects and charm your audience
with a mix of polite confidence and urbane sophistication (it's worth a try at least).
Male conversation is a whole new world. Just sit back and observe… then get involved slowly as you begin to feel comfortable. Not all men join in a conversation and it is quite acceptable to "sit it out" without appearing rude or out of place. Banter is an arcane art - best learned by observation. Just take your time and relax - all too soon you will be talking bullshit with the best of them.
Sitting:
Men take up as much space as they need to be comfortable. Cross your legs with one
ankle on the knee of the other leg or cross one leg over the other at the knee. Feel
free to sit with your legs apart but don't be uncouth about it. Sitting with a degree
of decorum is more important in suits and formal wear otherwise you will look
uncomfortable in that particular standard of clothing.
Eye contact:
Look directly at people, especially other men. No coy, shy or sideways looks - be
upfront and confident, but not aggressive.
Public toilets:
Using a public toilet is a lot easier than it first appears because if nothing else,
men are far less observant that women in such matters. As long as you stay calm and
focussed on what you are doing it will be easy. The first time will be extremely
daunting and you may find it easier to develop a bladder of steel until you get
home - especially as you get used to passing and living as a guy. One method is to
start by using toilets you know will not be busy, or even better one that is likely
to be empty. That way you can get used to the layout, feel, and smell (it will be bad)
and to gain the confidence to carry it off even when you have to use a busy
toilet.
Walk in calmly and fairly slowly - don't rush or look nervous as this will just attract attention. Walk past the urinals and into a stall, use it, wash your hands (men are getting better at doing this so you won't stand out) and leave. Easy.
If the stalls are all busy, join the queue if there is one otherwise stand and wait. Don't start any conversations but if there is one going or one of the guys speaks to you, you can choose to respond or not as you feel comfortable. Any comments should be brief and stay on the level of light banter - the toilet is not the place for esoteric philosophical conversations or meeting new friends, unless you are in a toilet looking to be picked up in which case do whatever it takes. If there is no queue and no sounds of anyone coming out you can still stand and wait. This can take a bit of balls especially if other guys are walking past you to you the urinals. Alternatively and assuming that you are not in a desperate hurry, just walk out and try again later. Remember that lots of guys prefer to sit and/or use stalls so you won't attract any attention unless you look uncomfortable.
One last thing - remember that the and doors on stalls often have gaps and that the walls don't go all the way down to the floor so avoid dropping your pants all the way to your ankles, especially if you have a packer attached. Keep any packing device firmly under control particularly if you have had a few beers - you do not want to be picking it up off the floor in full view of a bunch of guys you barely know (or your mates for that matter).
The above techniques should see you through most situations and with a bit of practice and confidence you will blend in comfortably. Don't worry about being perfect - no one is: the only thing that matters is you are happy with who and where you are.
For further information refer to the grooming and clothing sections.