A Kingdom For Keflings (PC)
Potions obtained from the Wizard's Tower cannot be used until you build a Factory or Castle Workshop.
Build the Artist's Plaza and Dye Mixer then accept the "Paint By Numbers" quest. Complete the quest to get the Magic Staff (upgraded Digging Bar) as a reward.
Creating magic gems
After a Witch's Hut is obtained (after making a Guild Hall), it will convert harvested crystal shards into magic gems.
In order to unlock the Cathedral, you must build the Dye Mixer Upgrade, the Tailor, and the Manor.
You cannot get all of the blueprints on the same playthrough. At a certain point you will get two quests from the mayor. One of them requires you to build five Offices, which will unlock the top right set of blueprints. This lets you harvest wool and wood faster. The other quest requires you to build five Curios Of Fortune, which will unlock the set of blueprints underneath the other set. This lets you harvest crystal and wood faster. However, you can only choose one of those missions to complete. Thus, the other set of blueprints will be unobtainable.
Unusable wandering Keflings
If you find a wandering Kefling that will not accept a task, it is probably due to their house being knocked down. Keflings will not work until you give them a place to live.
Getting player banners
Create an online game. When other players join, ask them to build a banner tower and place it somewhere in your town. Unique player banners are needed for the "World Traveler" and "Friend" achievements.
There are six textbooks in the game. One each appears after the Guild, Primary School, and Secondary School are built. Two others can be found lying around in the open. The final textbook is hidden under a nonrenewable resource.
Monty Python reference
After building the Town Hall, accept the mission to gather 50 pieces of Lumber in your Basic Workshop and finish it. When you get the message for completing it, it will be "He's a Lumberjack and he's OK", which is a quote from Monty Python's "Lumberjack Song".
"For The Greater Good" mission: Easy completion
Do not pick up the Keflings before kicking them. Simply face them before kicking them.