So let's talk about planning out a good game. Here's my theory-inspired method; tell me about yours.
First, you need ideas. They don't need to be fleshed out. Just "I want to run a game with A, B, and C in it, in a world like X" is plenty. They do need to be things that you like and are enthusiastic about.
Second, you need players that you can enjoy playing with, and who can enjoy playing with each other. This is all about the personal-getting-along; I've got a list of a dozen or so things somewhere about stuff they can do to get along better at the table, but at base, you need a group that's ready to have a good time.
Third, you need to find out the different stuff that these players like in a game. This doesn't need to be in any special format; it can be as simple as anecdotes of which games were great for them in the past. Your game planning will be tricky sometimes if the players all like very different things, but so it goes, sometimes. If you can figure out stuff that all of them enjoy - common fun - then your job gets a lot easier. If something that they all like can actually drive the whole game - central fun - then it gets easier still. But don't kill their potential enthusiasm picking at this stuff; their enthusiasm is actually more important than many picky details of preference.
Fourth, take your ideas to your players and pitch them. That is, try to get the players to look at them and start thinking about what they want to do with the ideas. The moment a player wants to play and starts to riff off the ideas, coming up with their own stuff, shut the hell up and listen really carefully. They are telling you stuff that they want in your game, stuff that you can give them. Bring a pencil and scrap paper if you must, but remember this stuff.
Fifth, take those ideas and that stuff, and put it together so that you can reference it as the game goes on, and flesh it out with all the other stuff you need to make the game roll. Check your original idea for what game system to use. If needed, make adjustments so that all this stuff you have can come out in play. Or swap systems if that's needed and appropriate. If you're really crazy, homebrew a new system. If you're completely off your nut, write a whole new game just to fit this stuff.
Sixth, get those players together with each other and with the material. Pitch, again, the new stuff and the big combination, just to make sure they like the sum total. Make notes and, if needed, adjustments.
Seventh, it's time to get down into the dirty work of making characters. Keep the players together and toss stuff around. As you're building characters, look back over that stuff that people like to do, and encourage the hell out of your players to absolutely load up their character chock-full whatever stuff the characters should have for a game with that kind of stuff in it - skills, personal conflicts, thematic material, whatever it is, this is where you try to front-load the hell out of the characters with stuff to do. If you have common or central fun available, try to get everyone to load up for those especially hard.
Eighth, look at those characters and their stuff, and build up the starting situation of those characters, and all the setting material related to it, so that big heaping piles of that same stuff is going to start coming out right after gameplay begins, and will keep being hit as the game goes on.
And Ninth, run that game. Keep hitting on the stuff the characters have; any time the players move into a new situation, throw in more ways for them to keep hitting that good stuff. Use slack time to "reload" characters with more good stuff. Use crunch time to bring it out.
Don't forget the snacks, and remember that a good story starts with an explosion, and builds from there.
So. How do you do it?