Where is the casino? In the US? If in the US East or West Coast? All important factors - very different styles of play.
Some quick tips:
1. When you first sit down, fold your first dozen or so hands unless you have monsters: AA, KK, QQ, JJ,TT, AK, AQ maybe AJ. This will give you time to observe the table, see the type of players, and give you a good, tight table image.
2. Try tipping the dealers between 5% - 10% of your winnings. If you take care of them, they will look out for you and typically will be more patient if you make a mistake, give you more time to make decisions, etc.
3. The whole see your cards thing is overrated. It will rarely happen that a player demands to see your cards in that situation. A good thing you can do, especially on a "friendly" 1/2 game is show your uncalled monster hands in the beginning. This will make people like you, respect you and less likely to call you later on when you decide to take a stab at the pot.
4. Some casino specific rules you should ask about are:
A. Ask if the line plays. Some
casinos require you to count your chips BEHIND YOUR CARDS. ANY FORWARD MOTION BEYOND YOUR CARDS COULD BE CONSIDERED A BET. Watch out for that one.
B. Ask about their bad beat jackpot, any promotions, etc. Many times casinos will run "rack attacks", AA cracked, etc.
C. Ask about specific house rules, the dealer will tell you.
5. Do not talk to a player if he/she is in a hand and you are not.
6. Do not talk about a hand if you are not in the hand.
7. Don't be a day dreamer and have to be asked to post your blinds, pay attention and post them when it's your turn without being asked.
8. Always keep your hands visible and above the table. Don't keep them away or under the table - other players may think that you are cheating.
9. Don't openly criticize or commend anyone's play. Doing so could give other players information about your level of play.
10. Finally, smile, be friendly and try to get the table to like you.