Some important things to know about quests:

• Quests can only be accepted and completed one at a time.
• You must first accept a quest to begin making progress on it. 
• Quests which require you to earn gold are impacted by tithes to the parish, bribes to the villagers, and buying goods at the market.  If you spend too much gold while trying to complete this quest, you may need to abandon it and try it again.
• Quests which require donations to the parish are measured in packets of goods, more information is available here: What are packets?