A few random nuggets to add on to what is already posted.
1. Picture the scene. The game is absolutely throbbing. It is crowded and there are black chip skyscrapers everywhere. Is now a great time to try handing he dealer $5 and say "so...... how do you play this game?"
Play with the free apps before your trip, take the free craps lessons offered in the graveyard, try playing by yourself at an empty table. If the dealer is grumpy to you then, then they are doing their job badly. If he is grumpy toward you in the throbbing scenario above.... he is giving you a hint to jog on.
2. When the dice are in the middle of the table, make whatever bets you want. When the stickman pushes the dice out,
get your hands out the way. If you didn't make all the bets you wanted... too bad. It is absolutely on you to get in tune with the pace of the game. This might just be the biggest tip there is and will have you fitting in instantly if you can follow this.
3. A follow-on from the last point, while it might take you a while to learn the payouts, you can learn the payout order. It isn't random, when the dealer has paid the guy stood next to you.... you are next! (S)he will announce the payout (e.g. $14!) which is your moment to say what you want. If there is silence, or they already worked out you are a noob, they will just pay you the $14. Base dealers will like you a lot more if they only have to bend their back once for you each roll. The rest of the table will like you a lot more if you place your bets efficiently. Consider the example: "$14!. Silence..... dealer hands off $14. Player then says..... place this on the 4..... and this on the 5....... and this on the 10.... 1 minute later and 4 back bends later, you are all set! Conversely.... knowing the payout is now $14.... when the dealer announces "$14!" you could just drop a dollar and announce "press the 4,5&ten" and the job is done. A softer way is just to inform the dealer "press a unit" which on a $10 table, will take you up $10 at a time with them paying you the difference.
4. Saying the word "seven" at a table is like saying Macbeth in a theatre. Don't do it.
5. The general advice ITT is spot-on. Start off slow, and when it feels like it is too boring, add a bet. Ignore all the fire bets, centre action, just make line bets, place bets, come bets to your level of comfort. The game is very difficult to beat with flat bets, so do be prepared to press it up when things are going your way. You need to make enough in that hot roll to cover the 12 months of misery that will inevitably follow

In 12 months time when you next get what looks like a heater, let me know how you feel about the noob that wanders over with a $20 and asks "how do you play this game" and it will all make sense.... you'll be a seasoned and salty craps player yourself!
6. Whilst craps can certainly see the most curmudgeonly of patronage, keep your hands out the way, follow 1-5 and you really shouldn't experience any intimidation or hostility.