but what or where is the most effective way to sell these to others?
/shout or /ooc or preferably /auction from time to time
Also since it seems your in the area these quests offer some nice cash at early levels:
http://wiki.project1999.com/Jagged_Pine_Crook_Staff
http://wiki.project1999.com/Rabid_Grizzlies
http://wiki.project1999.com/Rabid_Wolves
What are some of the more popular low areas and are groups even a thing early on?
Blackburrow and Crushbone come to mind and yes groups are a thing from day one.
What are some of the first dungeons (and levels needed) to explore? I've found the aqueducts so far.
Head to Black Burrow adjacent to the Qeynos Hills around level 6, you can level up on the multiple gnolls at the gates then head in to level 15. Pretty popular place, one of my faves in the game.