Beginners Combat Guide
Know your enemy.
How to not die (as much)
When NPCs aggress, they will draw the whole group with them. So when you are first about to engage take note of how many are around, which are part of the same group and which aren't, and what level/type they are. When you get aggro and feel like the fight is not going your way, retreat! Drop your locks and run in the opposite direction, use cover to block line-of-sight back to the NPCs to block some of their shots, and keep going until they drop locks on you.
NPC factions, types, and levels
Where to find NPCs