So, I just prepared a hook for a campaign. Actually, I was inspired by Jordan's thread and here it is what I created in a couple of minutes:
A technocrat roman emperor fighting off an otherwordly evil by corruption and force
My steps were easy for me. I'm a very visual guy, so I imagine already scenes and locations and how NPCs might talk or how stories go, even if I just read "roman empire" or "otherworldy evil" and soon connections are created between those
factions. Yes, factions, motivations and cinematic impression is what leads my stories on. I was intrigued by those words and the world of imagination just rushed at me.
Afterwards, I will tweak this or that relationship, but for the time being, I have for myself an impression about the tone and genre I want to create, maybe even about story I want to tell.
Second, I imagine the most interesting position the PCs could start in. An origin story so to speak. In presenting the leading factor of the campaign right at the beginning, I will make the course of the adventures clear. E.g. like I did in my summary above.
Third, usually I already have a couple of players who want to play, so finding them is not an issue. More to the point, it is mostly me who has no time to actually GM a new campaign...
And then, every other day my mind fills with ideas for the campaign and I write them down and get all hyped up and my players also. Until we eventually play the first session, I may already have written books about the world, NPCs, all kinds of things. I could already run the campaign for ages. And this is my mistake. I have hardly ever completed a campaign and it is nagging me and my players alike. And this is where I need to improve.
Roughly quoting
@JohnnFour here:
"What is the goal of a campaign? It is to complete it."