1) Leaders must be enthusiastic and enjoy the game!
2) Before you choose a game, be clear on your purpose:ice-breaking, learning names, breaking up groups, calming a group down, etc.
3) Choose games appropriate for the group - age, room, equipment, time. Games that involve everyone are better than games that exclude.
4) Prepare more games than you will need.
5) Make sure the room and equipment are safe - eg. Strength of chairs etc.
6) Know your instructions well, and explain them clearly and concisely - remember it is better to demonstrate than give long explanations.
7) Observe the group closely and notice their mood. Are they hyped up? Are they bored? Are some people angry? Are some left out? Be ready to act decisively.
8) If something is not working, forget it and try something else.
9) It is better to finish a game too early than let it go too long - all games become boring eventually!
10) Sincerely thank all people for their involvement - even if it was minimal. If there was a winner, congratulate them appropriately and perhaps give prize.