This is somewhat a large topic I think, Im not searching for “the best solution” but more how you do it and for what type of games that work or hasn’t worked (more a la post-mortem perhaps).
You write a script, images, “inside character thinking” or character design?.
You have a set of prebuilt assets that you use for prototype fast?
You use simple box and things like that and do the mechanics first?
You write all your ideas and then sometime you return to one and do it?
You use/search for prebuilt scripts, assets and start prototyping?
Also I ask because someone once said me that if you gona do something, you need to do “OK”… I mean we where working in the same software with purchase of images, so in my standalone work I have black, red, green images like samples of the real images, but he have some “nice images” about know characters, and that make the app even it was not working look more nice than my only 1 color images :).
You’re massively over-thinking this. A prototype isn’t barely even planned, it’s a proof of concept. Get some cubes going and some basic code, if its fun, its fun. If it’s not, get rid of it or change it
Having “nice” images or a “set” of prototype images kind of defeats the purpose entirely. If it doesn’t work with cubes, it’s probably not going to work.
generaly i just slap together a tone of stuff not a good plan i think once i made a city on paper then modeled it, i was crap at modeling then so it looks horrible but its design isent terrible sometimes things look better on paper so dont think of a design in your head or on paper as the law, more just guideline.
like Hippo said, a prototype is just something that works. Don’t even bother with art / mood /story. Just get the game to a very bare minimum and see if it works well and plays good!
So a prototype in what part of the workflow go? should my question be
What is the workflow that you have used to have a game? (think, write, prototype, feedback, get a new pro to with corrections, first thing not so proto, etc.).
A prototype is a barely-working first iteration of a game idea. It can be as simple or complex as you want, but most people choose to keep it extremely simple. Its sole purpose is to determine if the game mechanics are fun, or if you’re wasting your time.
With that in mind, it should be obvious where it goes in the workflow.
Actually I think I have a pretty nice video that could be/display one form of (rapid) prototyping. The first part shows how only Unity primitives are used to test the actual gameplay (which we tested in the webplayer).
Then there was a first superquick art draft introduced so we could get a better feel for the game since the prototype proved to be fun and was worth to take further.
Prototyping example:
Then we kept adding more and more stuff to the art sector while the gameplay was taken further
Obviously I’m not posting the current state of the game, to not get marked as a hidden promo.
not a good plan i think once i made a city on paper then modeled it, i was crap at modeling then so it looks horrible but its design isent terrible 
sometimes things look better on paper so dont think of a design in your head or on paper as the law, more just guideline.
