LOTRO has a color description for each level group:
Grey - Enemy is 9 or more levels below you (you get no XP for the killing)
Green - Enemy is 6-8 levels below you
Light Blue - Enemy is 3-5 levels below you
Blue - Enemy is 1-2 levels below you
White - Enemy is the same level as you
Yellow - Enemy is 1-2 levels above you
Orange - Enemy is 3-4 levels above you
Red - Enemy is 5-7 levels above you
Purple - Enemy is 8 or more levels above you
Ranks
Swarm (Green): some nature mobs, bats, roots.
Normal (Blue): wolves, humanoids, these is the common group.
Signature: the one of a kind… harder to kill but still soloable.
Elite (Eye of Sauron): hard to kill.Require special skills combinations or small fellowship.
Elite Master (Eye of Sauron + 4 Spikes): hard to kill. Requires Fellowship.
Nemesis (Elite + 6 Spikes): harder to kill.
Arch-Nemesis (Elite + Flaming Eye): Nazgul and other creatures.
DO NOT use Rain of Arrows unless you are confident about the area of effect (AOE) that you will cover with this skill since that can get the attention of adds (aditional mobs around the area). It is a bad habit to use that in crowded areas and get more mobs into the fight.
Use Precision stance instead of the Strength Stance it is useful because it does not generates so much threat and decreases the power consumption of your shots by 10%
This is a list of some great fellowship maneuvers I learned:
6 Players
GRRRRB / GYYYYB: does damage, restores morale and power and brings an oathbreaker.
3 Players
GRB (this one is amazing): restores 250 morale for some seconds, power and does some damage.