A little bit of quick advice for new players:

It is a brutal campaign; we do not pull punches or fudge rolls. I know many people have a problem with the death toll and their players would rebel if they died that often. We were in our mid-30's when we started playing Chainmail fantasy and late 30's when we started playing OD&D. Character death is not a failure, it is a learning experience. What many people call Meta gaming is just smart play. 

Here is what OD&D says in the Introduction in Men & Magic:

…and keep the rules nearby as you play. A quick check of some rule or table may, bring hidden treasure or save your game "life.”

OD&D assumed that you as a player knew everything there was to know about the rules and the game world that was available to know, hence the house ruling nature of the game to keep it fresh.

A little bit of quick advice for new players:

1.      Do not depend on the dice to get you out of a jam, because they will let you down; instead learn to anticipate and avoid being in a jam.

2.       Be familiar with what your character can do, especially Magic-Users and Clerics, know your spells and the details of what they do and learn what ones are the best to take for any given situation.

3.       Always know what equipment you have with you and what magic you may have and what it does. Do not die because you forgot you had something with you that could have saved your life. Know the limitations of magic and magic items.

4.       Learn about the intelligence of the monsters you face and their strengths and weaknesses. Also be aware that monsters in widely separated places may not be identical in these things and that differences in appearances from the ones you are used to are likely different in other ways too.

5.       Learn to minimize personal risk for yourself and for the group. Always remember that you are a team and have each other’s back.

6.       Remember that you will develop a reputation, you are not anonymous, and if you never show any mercy or forbearance, you will never receive it.

7.       Death happens, TPKs happen, dying is part of living, get over it. No moping around, roll a new character so the ref can work you back into the game.

8.       Always remember that the bad guys do not fight fair. Only Paladins and the best of the Clerics fight fair, everyone else usually uses any trick or advantage they can.

9.       Create allies and do not create enemies when you do not have too.

10.   Remember you are out to explore and garner treasure. Combat will come to you more often than you want, so do not seek out combat when you can avoid it. Staying alive will be tough enough as it is.

11.   To maximize fun, and maintain harmony in your group, do not stab your fellow players in the back; they will make you regret it.

12.   Remember it is not about how many monsters you kill; it is about coming back alive. Hopefully you are coming back alive with new knowledge and treasure, but above all make it back alive.

13.   When the ref says, “Are you sure that’s what you want to do?” be sure and pay attention, it will save your life.