Hey Tadpole,
Don't give up. I've been right there. I think in this case FTMs have it a little different from the MTFs. We can have a male name, dress completely male, and society will still see a female because masculine women are common and accepted members of society. I was doing just that (name change, clothes), and one day I looked up and down the street in my liberal little town, and noticed a half dozen (probably female-identifying) women who were dressed just like me.
For the MTFs, male bodied folks embracing femininity seems to cause a more immediate stir, and your average person is probably more likely to be aware that an MTF at least identifies as something other than male based solely off presentation.
Over time your presentation will change a little as you learn what works for you and what doesn't, and the ma'ams will become less frequent, then turn into confused looks as people try to figure out what you are (hehe), and then finally to the occasional 'sir', and then always 'sir' and 'he'. It's definitely not an overnight process.
As for people you've told still misgendering you...give it some time. I've found that even people with the best intentions have had some trouble adjusting their idea of me (female --> male) in their minds. My own father, who has been a diehard supporter of my transition since day one, still calls me by the wrong name 80% of the time (but feels bad about it). I get 75% 'he' and 25% 'she' from a coworker of mine...depends on how fast he's talking and how much care he's using in choosing his words. It's not deliberate misgendering.
So hang in there and don't get to caught up on what others think right now. Focus on being true to yourself first.
