Metal gear gurus, I need your help with MGS4.

I have never played any of the first 3. 4 is my first. I bought it about a week ago, and have only played 1-2 hours. I figured out there is a certain dynamic to the game you have to follow...Keeping stealth and hidden. I haven't mastered any moves, tricks, kills, etc and haven't been able to stay alive past the first set of enemies...much due to the fact I can't stay stealth.

Any tips, or advice fellas? Keep in mind this is the first time I play any MG games.