Making a match-3? Read this:

http://greyaliengames.com/blog/match-3s-in-the-bfg-top-100/

If you are making one for commercial reasons then make sure it's the best match-3 ever. If you are making one for fun/learning, then no worries! :-)

The casual game market changes all the time. If you try to just follow the trend you're not gonna beat the ones who are setting the trend to market.

Half the games on there right now are games where you have to search an image to find the items on a list to solve some kind of "mystery".

While it might seem like a good idea to make that kind of game because that's what's selling now, that won't be what's selling a year from now. I'm pretty sure people are gonna get sick of the "Where's Waldo" thing fairly quickly. Of course that genre won't go away completely, cause I'm sure kids enjoy it, but neither will match-3 games.

So if you can't go by what's in the top 100, how do you decide what to make? Well, I guess looking at long term trends might be a good idea. See what's remained popular for a long time. And what's remained popular a long time?

Well, puzzle games which involve matching things for one thing. :-)

You just have to come up with a creative way to do it, that's all. Why do you think Zuma did so well? And Bejeweled? There were plenty of match-3 games before Bejeweled. But they were tetris-like. Tetris was played out. Then Bejeweled came along and turned the idea on it's head by keeping the game board full all the time. And then when Bejeweled was all played out, Zuma came along and changed the shape of the game board, and had the player fire spheres at it. Which was sort of a variation on Bust-A-Move, which was another game which turned the genre on its head and was hugely popular as a result.

So really, the key to success is not to avoid making match-3 games. The key to success is taking a proven forumula and giving it some kind of unique twist which radically changes things.

Isn't that how games always worked?
1. Take known working elements
2. Invent new elements to connect those working elements in a creative way
3. Make sure it resembles in some way and does not resemble at the same time
4. Simple at first, hard to master will bring the success as it creates addiction (human per definition are perfectionists, if they see the chance to master it they will attempt the mastery. If you "allow" them to compete against each other that will only make it more addicting in most cases)

the days were "new" stuff was invented are long gone ...
main problem is step 2 and 3 logically and the "hidden" step within it: abstraction -> what are the elements, which of them were causing the success etc?
Even for a simple game like tetris this break down won't be that simple thought far simpler than for a more complex game

yes, good points from both. I think Dreamora's point 3 is very important. People like playing (and watching, and listening to) something FAMILIAR. So if your game breaks the mould too much, there's a big chance it won't be a success because it won't seem familiar enough to casual players. So the trick is to try something new based on a familiar gameplay and/or theme but you'd better make sure that the rest of the game is very polished and that there's a meta game/story these days.

Ah well, back to the drawing board.

the similar but different rule works I think.

I have this arguement with my girlfriend that I like to play a varied set of games, and like to see big differences with sequels and beleive genres should change over time.

She plays a lot of RPG's and says it's better when everything is kept consistent, and really only the scenery and the objects change, big changes to the structure of games makes her annoyed as she has to relearn how to play RPG's which she classes herself as already being able to play.

I agree to point, I don't want to get the next dead or alive game on 360 and find all the moves have changed, I want more moves and better graphics, but don't change anything from what it was.

Well it's like surfing you know? You ride the wave while you can but at some point you're gonna wipe out.

...or reach the beach.

"You ride the wave while you can but at some point you're gonna wipe out."

.........or taken by a shark...lol