That's my point. The whole thing seems like just a good fantasy coming from OP. If OP had been atleast a bit serious about his game, he would have notes written down, sketches drawn up, probably even an alpha version, especially now that it has been a year.
But I can get that the OP is looking to push himself out of that state. In which case, I recommend a little, unlined notebook everywhere you go. Ideas aren't thought up while sitting down, sipping coffee, waiting for it to happen. Ideas will pop up any point in your day and its your job to take it recognize it and jot it down as soon as possible.
As someone who doesn't really make games but rather in the advertising environment, I suggest you don't think too deeply when cooking up ideas. Of course, this generalized idea only works for base ideas like what your theme for this world will look like for example.
Also google mindmap, its a really good way for conceptualizing ideas.