To get completely comfortable at a poker table full of strangers you must have experience. Experience and be a studied up player. Study everything you can because this will teach you how to handle all the different spots you will be in and how to handle your competitors. The more experience you get the more comfortable you will be. Good luck!
@dannystanks took the words from my mouth, that's the same advice I would give to you...
The more you study more confident you will be... Confidence IMO is something you 'can't ' fake... You do have the confidence or not. and if you try to 'represent' confidence it will be more likely to this regulars notice that on you(and in other beginners as well)
sometimes you can use it in your favor, but the main thing I can tell you, just play, enjoy your time, and play carefully with your
bankroll, if you're not in the mood to play, then don't go... your wallet will thank you later