Just a short info for those who, say, have stronger SW background compared to MMO background:

The game uses tank/healer/dps system. This means that every party member has his/her own designated task.

TANK - make enemies (so called mobs) - attack them instead of other party members.

HEALER - heal wounded party members and evade all enemy attacks.

DPS - damage enemies and evade all enemy attacks.

Team must cooperate to make this working.

So first of all you need to know what is your role and if the group is forming just tell the leader what are you going to do. If you are a beginner your best choice is to play DPS. Your select your role at 10th level when you select your specialization and the skill tree.

Once you know your role, you do your job.

Tactics for TANKS: you are positioned at the group head. Find the strongest mob in a group, attack it and if needed taunt it. Taunt is your most important special ability you have learned from your trainer or will learn soon. Taunt needs to be on some easily accessible spot on your action bar. When you see mob attacking healer or dps (in this order) attack it and taunt it. You need to make the mob attacking you. Healers and DPS are less damage resistant and die fast.

Always turn the mob away from the rest of the group so if it has some cone attacks your team members are not hit.

Tactics for HEALERS: stay behind and keep the other guys alive. You need to make sure you will be able to heal for the whole fight. Use heals over time (HOTs) on party members and keep them buffed. Try not to overheal and wathc for your heals cooldowns.

Tactics for DPS: your task is a bit tricky, you need to damage the mobs and don't get attacked. First of all let the tank get aggro (make the enemy to attack them) . The tank is the first who attacks and you join in after the mob hits back at the tank. If possible position yourself at target's back, you will have some attack/damage bonuses this way. If possible don't pick up "your own" mobs since it's hard for healers to keep you alive when you play hero somewhere. Also all attack one mob - the less mobs standing, the less damage your party gets. IF you see that the healer is attacked protect the healer and if the mob started attacking and chasing you, run straight to the tank so he can taunt the mob. Remember that healer must be protected at all costs. Once healer dies the whole party is very likely dead, too.

The best order how to attack enemies is to get down the glasscannons (high damage, low armor) and weak adds first. So the tank gets the elite on himself and dps zerg adds and kill them asap then they go for the elite.

Crowd controlling - if you know what is a CC you likely don't need to be said what to do. However some people do not realise that there are skills which can "calm" an enemy.

So if you can see an enemy paralysed or hanging in the air and struggling to get free, leave it be and attack something else. This mob is harmless and if you attack it you will break it free.

Good luck teaming.