first off kids you have to go to the statue after you finish a quest and access it. you then go over to the quests that you finished that are green and say 100% and click them. you then say you want to redeem that quest or whatever it says... i don't remember off the top of my head. once you do that you'll get your reward...which in most of your cases is the very first key which allows you to move onto a new area.
now for the part about the unlocking quests that you can't do. you have to find a sigil around you and get the quest from it... but only certain quests are at certain sigils, therefore you have to find specific ones which can at times be irritating to get the newly unlocked quests.
i remember peeping tom being towards the far left of the map.... around where you forge the warriors shield. some of the quest bosses that the sigils tell you kill are in the immediate vicinity while others are a good 30 minutes of wandering around to find them. so keep wandering into new territory b/c if its wanderable then there's something there you need to do b/c anywhere ur not supposed to go is going to be locked
all i remember atm. happy hunting