Needless to say, the linear vs non-linear debate has been brought-up many times, and everyone seems to prefer non-linear games. With that said, I plan for a lot of linearity in my game. So...

How do you keep a game linear? Meaning, suppose a player is at town A, and the next plot point is in town B. If the player is capable of going to any town on the map, and if they weren't paying attention to the cue that hinted that they should go to town B, then they might end-up exploring the whole world trying to figure out how to progress the game (which is very bad). So how do you force or suggest that a player go directly to town B without making stops at all of the other towns around the world (which basically gives them the option of ruining their gaming experience by wasting lots of time)?

Some methods that come to mind:
-Some games have a world map like Super Mario RPG or Ogre Battle, where going from one town to the next is more like stage selection, and later towns won't be accessible until you reach that point of the plot.
-Several RPG's play off geographical barriers to limit your transportation options. For example, you gotta defeat the pirates to get the pirate ship. Or you gotta befriend the empire to get a ride on a boat (which they regulate). You gotta befriend the guy with the airship if you wanna get to the other continent. After some brief airship access, it crashes and you're back to walking. Town A and Town B are separated by mountains, and traveling across the mountains is like a dungeon in itself. Etc..
-A slightly more sophisticated thing you can do is suppose you have a mini-continent with three towns placed along a linear path with great distances between each one. In the first town is basically nothing that would hold your attention, so of course you begin trekking forward. There's such a long stretch of distance before you get to the next town that by the time you get there, your party desperately needs an Inn and an item shop. You don't have much choice about whether you pass over this town and see what else is out there, because your party is totally exhausted.
-Like Chrono Trigger or the RM2K game "Sunset Over Imdahl," you stay on the same mini-continent for the whole game, but there's a passage of time or time travel, so that the same few towns offer changes of scenery.

So... do you have any good ideas of how to do it? Any good variations of these things, or anything original?

The simplest thing to do is to not give the player access to the world map. If need be, you can still use it in cutscenes or events meant to show uneventful travel/passage of time. But if the player is only meant to go from A to B and then C without anything in between, making them walk those few steps on a world map is pretty pointless.

Once there is something to explore, then you can give the player access to a world map and set up plot-related devices that will guide them away from certain areas. Things like needing a boat to get to the other continent, or needing a key before climbing that tower, and so on.

Edit: I hope I didn't come across as rude. My project is very linear in the beginning, so this is what I chose to do.

I came-up with another geographic barrier technique. It might sound cheesy, I dunno. But I was looking over my RPG ideas and saw one for... you ask a powerful sorceror to cast a powerful utility spell for you, and you can't pay him, so you have to go questing to bring him back something in exchange. Maybe that powerful spell is a teleport spell to another continent. So it wouldn't be super different from getting a boat ride, but it would justify more otherwise pointless questing, and it would be logical. If someone said you can't get a boat ride unless you bring them a rare item, the hero's response might be "Why? Boat rides are pretty cheap for everyone else." Powerful high-level spells... they aren't cheap.

I personally find to much linearity makes the game become a tedious drag, Final Fantasy XIII for example. The game was competent in regards to graphics, characters, design, and execution. But I felt confined to a crawl space in exploration, this made the game unappealing really fast. Final Fantasy XIII felt more like a movie then a game, if they allowed more sub-quests and greater exploration the game would have been much better. A great example of a fun game is Megaman Legends 1 and 2, not only do you have the main story to accomplish but you also have a great number of extra things you can do. There's the sub-quest of weapon making, looking a Role's diary, you can even influence how people react to you based on how much damage is done to residential areas while on a mission. These things give the game immersion and flavor, keeping players interested even after they are through playing the game. Players can look around for hours hoping to find something new and when they do it's exciting.

The best way to have some linearity is to have a goal for the party, for example bad guy blows up city, player witnesses the tragedy and swears revenge, he finds out where bad guy lives by asking questions, player confronts bad guy and wins. By giving a set main-goal the player knows what is the greatest priority in the game and can go accomplish it.

Also a good way to build barriers is to place enemies who are way above the player's level, this seems more plausible then say a fence blocks your way or a single guard, these types of things infuriate the player. Think about haven't you ever wondered why you character can't climb over a picket fence? Instead your forced to tread through a dangerous mountain pass to cover as much distance as you could if you had just climbed over the fence.

I, on the other hand, don't always feel that linearity is always necessarily a bad thing. Some games the focus is not on your narrative choice, but on other aspects of the game play, and as such, it make sense for the devs to give you a linear storyline.

now, in the context of an RPG? yeah, linearity is almost always to the detriment of the game, since it fundamentally means it's less roleplaying and more sideshow watching. However, even then, I do feel it can still be a valid game design choice.

In my experience, the best way to put on linearity is to simply not give the player the option to explore the map at if linearity is your goal. Otherwise, you're just teasing the player. What's the point of having this huge map to explore if there is only one thing on the entire map for you to do or that there is only one thing that you could possibly succeed on?

Yeah. There's just a few reasons I want to make my game linear...
-There's only 9 characters in my game and you can have up to 6 in your party at one time. I've already pretty much finished eventing all of my custom systems, save a few bugs, etc.. So it's too late to increase the number of party members, and I want to make sure the player picks-up all 9. I don't want them to just not visit a given city, or a certain character in that city, or w/e, and fail to pick-up a party member. There's no walkthrough to tell them "make sure you get this character in your party" like there is for a professional game.
-There's a lot of storyline cues, dream sequences, etc. that require variables and/or switches. Instead of having hundreds or maybe thousands of such switches and variables, I'm kind of cheating by having about 20 map variables and overloading them by resetting them when you get from one plot point to the next. I dunno, maybe I should just decide to make hundreds of switches instead, I'm sure it doesn't take-up a ton of memory.
-Since this is an amateur game, players tend to have ADD about playing all the way through the game. Therefore, I want to eliminate things that "waste the player's time" like feeling compelled to talk to every NPC, explore every part of every town, having the option of exploring every town in the wrong order and then exploring the town a second time when they're SUPPOSED to be there, etc.. That way, they can get through the full game experience quickly while hitting all of the core plot points and waste less time on pointless exploration, grinding, etc.

You want the player to pick up all characters. That's not difficult. Tie in events that lead you to this character joining you. I think part of what you're really looking for is believable ways and techniques to add party members.

Also, it sounds like you're trying to keep the player from running around too much, and sticking primarily to story-line focus. You'll need to keep the transfers interesting then. Make sure there's plenty of cues as well to what needs to be done next for the story to progress. Instead of NPCs telling you this and that, maybe they can tell you what you were doing, like "Oh, John, yeah he's up the hill there." or "The monster is on the loose."

If you want to keep playes from grinding or talking to NPCs or running over the place, make sure you put NOTHING in that would give them a reason to do that. Make sure NPCs never give information beyond the story, that the only items are available in a linear fashion, and the next set of enemies is always right at the right level/strength for when you run through the dungeon. If you break this rule, you will have to break it completely, not just once, or you may frustrate the player.

I have zero issues with linear games. As a matter of fact I started to think that people are beginning to forget the meaning of non-linear but that's neither her nor there.

I guess you could use switches from prevented the player from going into certain towns. Maybe make the character say "I'm not suppose to be here" Or something like that. You get the point, right/