Thanks SoggyShorts for your advice. I hardly decline quests. For some strange reason, I think I'm missing something important if I do. But I've been completing the quests daily, even the declinable quests. So if we are about to unlock a chapter where a new guest race will arrive, we need to start declining quests until we see the main quests appear? Is that correct?
Not quite what I meant. You said you were deep into dwarves before you started getting dwarf quests, and by this I thought you meant the declinable ones.
There are 2 quests aside from event quests.
1. Main/storyline quests-- these must be done in order, and for the most part cannot be declined.
2. Declinable/secondary quests. These can be declined as much as you like, and are on a cycle, so if you click decline enough you'll just end up back at the quest you were on.
I think(not 100% sure on this) If you don't stay current with the Main quests, then your secondary quests will not advance either. But if you are current on your Main quests, then the secondary ones will advance, and ask you to produce more goods and give greater rewards.