Patience is key. Pay attention to your opponents but don't "stare" them down in the eyes. Honestly, you rarely want to make eye contact when involved in a hand. I'll check out my opponents body language during a hand by glaring over, but other than that I'm typically looking at the board. Play tight, only Premium
hands. Play small-medium pocket pairs for cheap only looking to set mine and occasionally suited-connectors if the price is right. Don't "Hero" call with marginal hands, its not tv and its okay to fold. Stay off your phone if possible. You don't want any type of distractions. Try to keep good posture at the table also, it actually helps improve decision making.
And one more thing, Do Not Under Any Circumstance Drink Alcohol!
Hope this helps. Good luck!