This isn't just about games now is it
The problem is that we all get that small snippet of pure joy when we imagine something. The two best lines of the song that we base a verse around. The climactic finish to the story we base about ten minutes of plot around. That one fight for the game.
And so on.
And yet, with practice comes development.
I'm a budding song writer. For years I've been writing strands of lyrics, short segments, then pulling my hair out when I can't turn them into full songs. Practice made me able to write full songs. Lyrics anyway.
So I got bored of just that and picked up my bass.
Close my eyes at night and I can hear the full song playing, I bet I'm not the only one, but I don't know what chords I'm hearing or what rhythms I'm hearing, so I can't record it.
You want to finish your epic game? You have to learn how to map,write,sprite,etc perfectly. It'll always be sub par if you're just not skilled enough to pull it off. This is why a lot of people prefer to work in groups. There aren't many one man bands, aren't many TV shows written by one person alone. No Film made by one person alone.
The list goes on.
If you can't quite put those lyrics to paper, then practice it over and over.
To learn how to write, take a notebook with you EVERYWHERE and write in it at least once a day. Only write what you consider a masterpiece, or a mini masterpiece.
Artists do pretty much the same thing.
I imagine a skilled coder is never too far from a place to jot down his code.
What magician doesn't carry a pack of cards?
In fact, anyone who ever wants to make anything should ALWAYS have a notebook on them. After that the masterpiece builds itself.
Some masterpieces take years to come to fruition and start dirty, they get cleaner, cut, like diamonds.
The trick is not to give up on them, you could say.
For inspiration, my dad just finished a 160,000 word novel. The research and writing of which has taken him a decade.
But it's his masterpiece.
Anyway, that's the end of my ramble...