Yeah, it's got an incredibly steep learning curve. The best advice (other than the stuff in those guides) is to play carefully, but also not to get too attached to your gear. You WILL die.
At first that's all you'll do, but eventually you'll get good enough to survive for a few hours or days. Soon enough you'll be completely self sufficient through hunting and rarely need to go to town. Then you'll die from something random like hitting prone in a doorway and taking a million damage for no reason. It's an alpha, weird instant-death bugs happen from time to time.
As long as you learn from your mistakes and can laugh off the stuff that's outside your control, you should have a great time.
Oh, and don't ask someone if they're friendly. If they say yes, they're still likely to shoot you. Watch how they move and act, and judge accordingly. Or shoot on sight, that's how I roll.