As you know, for indie game developers, game design is everything, especially game design that can be sold!
It is problem of life or death, key point of divider whether wasting 6months~years of himself or few developers and thousand of money or successfully withdraw money big more than investment and time invested.
I think All is up to [Game Design(Game planning)], isn’t it? So what game should be maked? and can be maked? within few months?
So for solo developer or few guys team, what is good strategy? Who can do this job good? Who can teach this?
All I can say about planning for a game, is to make sure it’s unique and never been done before. I know that’s not really not what you were looking for, but it’s something everybody notices.
Read books, read the internet. Study games and then make them. Sorry, not sure there is a simple or accurate answer to that question. If you want to be a doctor or plumber the rules and skills are pretty set in stone and have been around for years. People are still pioneering the area of video game design. There is certainly many things you can study and learn to improve your game, but a lot on the principles of effective game design. but coming up with good ideas in the first place, that is the tricky bit, with no simple answer.
A lot of the time (I think it was truer in the past than today), people get into Independent game development because they have ideas already that they want to make. It is that passion that drives desire to develop. I think you will find with most game devs, that they have more ideas/concepts than they have the time to work on. And certainly almost every successful indie game is a labor of love, and have the persistence to build the game they want to build.
If you are approaching it strictly as business and don’t have the ideas for game(s) that want to make already, it probably won’t work out very well. Virtually every indie success story began with a concept, not as way to make money.
Make the game you really want to make. I really believe that is the whole point (or should be) of Indie game development. If you want to make money, there are a lot easier and less risky ways to it than making games.