[quote=@Odin]So, would you say that it is best to organize a story prompt like so (as this is the image I get when reading your description but I'm a slow person so I might be misunderstanding):

[center]Title of the RP: The RP of RPington
[insert image]
[sub]dark | gritty | bad writing | racing cars | also dogs[/sub][/center]

[hider]And then the actual 'explanation' goes here?[/hider]
[/quote]

It's one I'd recommend and use for myself. It's easier to scroll through if you have a large number of prompts, ideas, plots or suggested material. An image may not be necessary unless it's scaled-down enough and applies to the narrative. But you've pretty much got it down.
This is how I use it:

[quote][indent][indent][indent][indent][sup][i]title. -- sub-title if applicable or a summarization that fits into a sentence or less.[/i][/sup][/indent][sub][sub][sub][h3]themes ◆ subjects ◆ terms ◆ possible restrictions◆ etc.[/h3][/sub][/sub][/sub][color=gray][sup]_____________________________________________________________________________________[/sup][/color]

[indent][hider=&][sup][color=silver]and the rest is history.[/color][/sup][/hider][/indent][/indent][/indent][/indent][/quote]

I prefer smaller texts myself and love to use the [code]indent[/code] feature. But you can easily strip the [code]sub[/code], [code]sup[/code] and [code]header 3[/code] tags:

[quote][indent][indent][indent][indent][i]title. -- sub-title if applicable or a summarization that fits into a sentence or less.[/i][/indent]
themes ◆ subjects ◆ terms ◆ possible restrictions◆ etc.
[color=gray][sup]_____________________________________________________________________________________[/sup][/color]

[indent][hider=&][color=silver]and the rest is history.[/color][/hider][/indent][/indent][/indent][/indent][/quote]