For me the proces of creating a game from start to finish is unique for each game.
looking back however there is a mayor path im on.
I have 7 game prototype's: 4 small, 2 medium 1 large production.
The medium ones are waiting for my new skills in creating a good level editor.
The small ones i work on when i need a break from the medium or large productions.
They keep the flow of logic assessment and creation stimulation going.
Also they have the role of keeping the (i have finished this game) in check.
As working on large games takes a lot of time, it is key to stimulate finishing a production.
The small games help me with that.
In the large games all current aquired knowledge snaps into place so that game sets the tempo of my doings.
When i however come to a halt because that game needs more logic/creation value then i can offer at that moment, then i swich to one of the less complicated games.
This is how it works for me, and when i stumble uppon a great game idea the first thing i do is check how long it would probably take me to create it so i can calculate the future outcome.
understanding if a game is fun or not goes in that same proces.
When the game fits into my personal future profile, i accept it and build a prototype, and so forth.