How to be more comfortable when talking to guys?

dont get me wrong, i do talk 2 some, and a couple are like best friends, but all the rest, especially ones i like or even think about liking make me a totally different person. when i'm w/ my girls im loud, laughing, and carefree. when talking to the one, im blushing, quiet, awkward and very reserved. one of my biggest obstacles is my blush. it keeps me from alking 2 guys bc i know it will come through. and if i do say something, and they start talkin, i cut it off quick bc i just am scared. idk, its hard for me, especially if i like this guy, or ever have liked him.