This reminded me of this little essay.
Quest Building Guides (Types of Quests)
1. Kill and Fetch The simplest type of quest really to make is the “Fetch and Kill”. Players are hired to find something and kill the foes between them and the item. Often it’s as easy as find and kill the goblin chief and return with his head. These quests favor hack and slash responses.
2. Seek and Find Similar to Kill and Fetch quests, but you must find certain items. Often as many as you can and then return with them The best way to design a quest like this is to use a placeable, scatter several of them through a larger quest area. When the players open the placeable there is a search or a spot roll to locate the items you're looking for. This type of quest favors hack and slash, but gives players a reason to use spot/search. Being hired by druids to seek out coldberries that can be found only on the rare coldberry bushes located in the artic territory of a white dragon and its wyrmlings.
3. Escort Mission This escort mission is where the players must escort a non-player character through some hazards. The NPC can be a combatant aiding the adventurers like a henchman, or the NPC can be a non-combatant that requires constant protection during the mission. This type of quest requires some strategy from the players. Sometimes, pure hack and slash must be avoided. Escorting the local sage to a mysterious ruin so he can examine a strange artifact there that is too heavy to move but poses a grave danger to the local town is an example of this kind of quest.
4. Negotiations The purpose of a negotiation quest is to meet some NPCs and negotiate a settlement of some kind with them. This type of quest requires the players to make social rolls, such as Bluff; Persuade; and Intimidate. The quest can be combined with any other quest at the end, to allow players to increase their rewards. Players are hired to resolve a dispute between the local town and a band of barbarian raiders that have been attacking recently; the local mayor hopes the players can convince the barbarians to aid the city by raiding a rival town to the north rather than the player's home town. Hack and slash has to be avoided for this to work. You can also negotiate with the mayor to pay you more for the goblin chief's head after a Kill and Fetch. In another variation, the goblin may even surrender at near death giving the players an option to negotiate a peaceful settlement.
5. Solve a Mystery The players must solve a mystery. Perhaps they have to enter the local dungeon to examine a mysterious crystal, or raid a temple to an unknown deity. While killing the enemies they find is certainly welcome by their employer, the employer will call the mission a success only if they return with information on what is happening. This requires a successful Spellcraft or Lore roll most often at the end of the mission.
6. Defend a Location The players must defend an isolated hamlet from a horde of zombies when has been marching for unknown reasons across the land destroying all in their way. The citizens have all locked and barricaded themselves inside the town hall, but the players have to booby trap and defend the road and alleys of the town against waves of zombies that are marching mindlessly toward the town hall hoping to break down the door whereupon they'll slay all inside. This type of quest is very hack and slash, but requires lots of planning for success, and can be much more intense than a normal Fetch and Kill.
Another idea is to find other ways to require characters to need certain skills while on quests. Perhaps dwarves hire players to go into their orc infested mines to reactivate the golems that use to patrol there until the orcs sabotaged them and took over (requiring a Craft Armor and Spellcraft check to reactivate and repair the golem). Perhaps a merchant hires players to get an expensive diamond from his gypsy allies, but the gypsies offer three diamonds and only an Appraise check allows the players to choose the right one and exchange it for the rare tarot deck the merchant gave the players to pay the gypsies.
Incorporating skills into any quest tends to pull it more from the hack and slash level and more toward the role-playing level. It makes the quest more immersive, gives more reason to bring characters with skills, and encourages players not to focus only on 'useful' skills like Tumble or Discipline.
Finally, any quest should focus on a unique angel. Something to make it special or make it stand out a little, especially if you’re doing just a Kill and Fetch type of quest. Come up with a gimic or special effect to make things interesting. Maybe the goblin chieftain is forcing his goblins to ingest large amounts of sulpher; this causes them to explode randomly during combat. Perhaps the coldberries make the white wyrmlings’ breath more potent, and on a failed saving throw it freezes a player solid until they take fire damage. If the players fail repair the golem but fail to reactivate it properly it may attack them--or if they do very well it comes back into operation and helps them wipe out the last of the orcs. Perhaps the undead army attacking the village is supported by skeletal archers who’s arrows turn into more undead when they strike living flesh. Perhaps the gypsies with the merchant’s diamond worship Kossuth and made their camp at the foot of an active volcano complete with lava flows and the occasional flaming projectiles raining down from the sky. Perhaps the sage going to investigate the ruins with you reminds you that the ruins are cursed so that metal armor weighs twice as much, forcing you to use leather armor or enhance your strength considerably.