I am what you would call "very muscular, 6' 2", 225 lbs, and 4% bodyfat. The gym I went to went belly up, and we had to transfer membership to a racquetball/weighlifting place rather than the ironworks we used to go to.
The women at the racquetball club (several of the women I know told me this) were like, "look at the World Gym guys!" I take off my sweatshirt and go to a tank top only in the summertime at the gym, or when I've worked up a pretty good sweat. I might be in a tank top at the gym maybe one hour per week. My point is, women (and men) don't have to see the muscles all the time
Now, if you are decently muscular, you cover up. Why? Girls can see through clothing shape and know what a body looks like under there, just like we can figure out their shape pretty well even if their clothes are sorta loose.
If you are less muscular, but gettin' there, you wear something a little tighter, that shows the topography a little. Don't overdo it.
Do NOT, for God's sake, be one of those guys that wears short sleeve shirts in the winter to show off his biceps. Lame. If you do that your arms ain't so big anyway, and you must have an inferiority complex.
Play it down a little. The way I look, I play it down a lot. People notice anyway. As for conversation, be cool, back off on the dominant attitude a bit. People are pleased to find that a large, aggressive looking (I shave my head sometimes) guy can be interesting to talk to. Chicks like it when you're that way.
