Look at your hand only once and memorize it. Preferably when the preflop action comes to you not sooner. That's because many players give away their intentions when they look at their hand. Some players fold out of turn which gives the earlier position player positions knowledge of their action. And don't make the mistake, when there three clubs on the board, to have to look at your hand to see if you have a club. They will know you don't already have a flush because if you had two clubs you would have remembered that. Memorize both the rank and suit of your hand the one time you look at it.
Learn how to physically guard your hand so it doesn't get accidentally knocked into the muck. People usually do with with a card protector but you can also just keep your fingers on it. But don't cover it completely other players need to see you're still in the hand.
Learn how to keep track of the number of chips in the pot. You will need to add up the bets each round of betting to do that. It's going to take some practise but this is very important.
If you need to, at most places you can ask how many chips are in another's stack. It's typically against the rules for a player to hide a 10K chip below a pile of 1K chips but sometimes it's hard to see what a player has so don't hesitate to ask if its allowed.
Be careful about physical
tells. They can be misleading and that will cause mistakes. Body language differs from person to person. A signal from one player may mean strength and the same from another may mean weakness.
But do from the start pay close attention to your own body language. Keep in mind when you
bluff if they catch you they will pay off your value bets more in the future. So its not bad. And keep in mind when you value bet, at least when you don't have the nuts, they could call with the nuts. So no matter what you're doing, no matter how strong or weak your hand is, just be as emotionally indifferent as you can. That's really the way to play all the time so you don't get tilted. If you get tilted live it will be obvious to everyone.