Introduction
RPG(Role-playing-game) scenarios/campaigns are no doubt the hardest to make, successfully, this guide will teach you how to make a successful RPG scenario/campaign.
Credit goes to Artinald, HL_Reaper, Auron 2 and PseudoWalrus for sugesting stuff in this thread.

The Basics
What makes an RPG campaign different from a normal RTS campign? What makes an RPG scenario different from an RTS scenario? This guide talks about the basics of an RPG.

Name
A good RPG has to have a good name in order to be successful, you can't just name it My RPG, people like to see a good title for it, no matter what it is(as long as it doesn't use profane langauge(swearing)).
Character
Like your RPG title, your character must have a name, a good name, that suits your idea of the character.
In AoM:tT(Age of Mythology:the Titans) you can customize the name, armour, damage, hitpoints, population cost, and so on, using the Change name effect and the Modify Protounit effect, to customize your charecter. Infact you SHOULD customize your character using those. Furthermore your character must have a good personality to go with him/her, a history and a goal. If you want to go even more advanced you could add levels to your character, that improve stats based on unit kills and possibly unlock special abilities.
See:For more information
AI and Interaction
It is important and a must to add chat between citizens or whatever between your character and someone neutral or allied. Also, units should NOT stand still, move to point/move to unit effects or add and AI to that computer player.
Objectives
Ok, you MUST have objectives in your RPG, and in any scenario nontheless. This is what a playable scenarios purpose is, without it, there is nothing. Now it is good to also have side-quests in your RPG to complete for someone neutral(agian, assuming you have a vilage/city in your RPG) if you complete, that person could give you an upgrade, unit, anything, even items you could mix at places to create healing potions, the list goes ever onward.
Other:
Basic Ideas gathered from weeks, to months to years ago for RPG's
-Food heals
-Gold for money
-Favor for magic
-Entering a shop teleports you to a buying area
-Quests
-Kill dragon/monsters and "plant" teeth to make a army (Greek myth)
Realms that you teleport to and from
-Grassland/Mountains
-Desert/Islands
-Snowy/Caves
-Underworld
Military Arena
-Fight larger opposing army and win
Arena
-Death results in loss of gold and teleported back to town last visited

See:This, for more information
Gold
100% of the RPG's i've played needs gold, to buy food to keep your charecter alive, to by potions, upgrades, armour, weapons and so on, this is assuming you have a village in your RPG.


Map Design
First off, most RPGs use large maps or even bigger, say Gaurdian's KotM series used 512x512, to get such a map size, go to world->Map size in the editor.
Next, you must include eyecandy to make your RPG enjoyable, manually add your trees from the object selection window is also a good idea. Add wildlife, rocks and anything else that suits the envoirment your doing. Now the most important thing of map design is to mix terrians that suit your RPGs enviorment. Set your brush size to 1 and keep using different terrians, for more information, read this by Kumar Shah.

Story
An RPG needs an unique, fresh storyline to make it interesting, it needs problems and solutions, take it you were writing up a story at school. You could have problems that keep on getting bigger, that result in something bad.
Objectives should go along with the storyline. An RPG does not need to be long to have a good storyline.


Atmosphere
A good RPG trys to have atmosphere, to get such, use terrians, music, unit animations, SFX, sounds from the enviorment, cinimatics, and dialog to explain it.

Other
This is ideas that aren't necessary but are good addons

• Use day-to-night cycles. Basics cycles would use dawn,defualt,dusk,night, while advanced cycles could use Cheezy's World Map VX lightings.
  
• If you have this long path your charecter has to follow, make sure you have to follow it for 30 minutes max. Include multiple paths and/or puzzles along the path to make your RPG more interesting
  
• If you have puzzles in your RPG, make them chalenging, no to hard to get, not to easy to get.
  
• If you have a day to night cycle add sounds from the enviorment and possibly SFX.
  

Quest Vars in RPG's BY Battlestar
Ideas By BattleStar000 to put your RPG above all others(who didn't read this)


Normal usage of Quest vars
For control over quests
Quest vars are, as its name suggests, also very important factor to control quests. You can use it for easier reference of quest progress to have greater control. A classic example (From an mmorpg, The fourth coming) would be: before you found the nomad’s letter, the old druid says the same thing to you every time you click on him; after you found the nomad’s letter, the old druid will ask you to get his staff back; after getting the quest and before you get his staff back, he’ll remind you about it every time you click on him; after you get the staff back to him he’ll thank you every time you click on him until another quest involving the same druid becomes available to you.
Using quest vars you can easily control the druid’s speech since quest vars can easily identify before and after you finding the nomad’s letter, and also before and after you help the druid get his staff back.
Using quest vars you can control multiple NPC’s speech as well.

In the RPG template, taking an example of the potion sellers, they will sell you potions if the variable “quest” equals 0 (you can change that of course). That means you can use the same potion sellers to deliver quests, and when you finish the quest, the potion seller will sell you potion as usual.

For randomization
Randomized rain, events, etc. using quest vars will add replayability and more natural feeling to the map. Randomized enemy monsters are installed in the RPG template.

For rewards
As in the RPG template, if things are recorded on quest vars, you can use them to grant extra experience, skill points, stat points, increase a specific skill, etc..


For more advanced ideas

Extra options
In Geneforge, a turn based RPG, there is a skill is named leadership. At a certain situation, such as at where asking a thief to return a stolen item, you can ask it back safely by selecting “‘Of course you didn’t steal it, perhaps it was just lost in the grass’ and turn away” but the option is only available when you have enough leadership.
You can use quest vars to recreate the example above. Make a trainer to buy leadership, record it on quest vars, and when you have enough points recorded on “leadership” variable; the extra option becomes available to the player. Doesn’t always have to be leadership either, it can be “luck,” where special things happen only if you had enough luck, or “wisdom”, “athletics”, etc..
Since the RPG template’s stats, spells, and skills etc. are recorded on quest vars, you can do this with it.

Conclusion
Overall, RPG's are very hard to make, for there is a lot of 'MUST' and 'DO' things, plus you need skill like with story writing and the editor. I encourage practice with Quest Vars and such. I hope you enjoyed my in-depth guide to making RPG's, make sure you credit me in your RPG for this guide as i took my time on writing it, add this to your favourites if need be.
A class RPG template will be coming out in a couple of months, information on it can be found via My Links section .

I will be updating this guide with the latest RPG hints&tips for your convienience.
Got hints or tips for my guide? tell me and all add them

Links
Battlestar00's RPG Trigger Template
Hero Levels by CodeLabMaster
Terrian Mixing by Kumar Shah
Angel CheeZy's Guide to Objectives
Angel Kumar Shah's Guide to Using the Elevation Tool
Angel CheeZy demonstrates how to use Modify Protunit and Change Name(effects) and what they can do
godofexplosives of Tsunami Studios demonstrates 'Eye Candy Farms'
Angel CheeZy teachs the Basics of Overlapping buildings|Advanced Overlapping
A guide/template to designing an RPG by BYRNZIE
Happy Designing!!

[This message has been edited by jonathan1222 (edited 08-03-2009 @ 06:46 PM).]