Questions about new skills

Hi guys,
How do I get new skills? I'm a ranger/elementalist and I've gotten some from completing the "tasks" set by the one trainer in the mountains (for elementalist). I also got the pet skill from the one in the town to the south east. Are there other people?? Also, I hear people keep talking about pre-seering stuff too... Whats that? Finally, I got collectors but don't have an aura when I do emotes... what gives? Is there something special I have to do? I see all these glowy people and I want to be one too... Thanks much!
Sincerely,
MK