Even before first adventure I would say:
1) Find people who loves Middle-Earth, TOR is all about middle-earth, if characters, places and themes from middle earth are not going to be central to the game, I would choose another system.
2) Journeys can be very demanding for new loremasters, so if you think your players might travel to a certain region, I would (this is also for me a fun part of being the loremaster) read about that certain region and think about possible hazards, try to place some that might prelude the coming challenges ahead (a dead carcass of a cow, that seems to have been eating by a troll), later in the adventure the players might have to fight the troll.
3) Combat is interesting on TOR, but it also requires some creativity from the loremaster, (I wish the designers could make a book dedicated to hooks and clever ideas for combat, councils and journeys) combat will get pretty lame after a while if you don't insert some additional elements, for example, the group is fighting orcs that have taken about an advantageous position on the cliff, there is a path but it is narrow and is defended by an orc guard (that only one character may engage due to its narrowness). The group will have to decide: shot arrows at the orcs above the cliff (-1die due to the height), or fast kill the orc guard to move above and engage them, or climb the cliff (requiring athletics rolls).
Other lore masters here will probably have better tips