I believe one's creativity really comes down to the ability to tell a story and pace it out correctly. So often I witness and experience roleplays where people push too hard and too fast early on, that they use all their ideas for plots in the initial character sheets, and when it comes to the roleplay they are already trying to write the conclusion to these stories as a beginning instead.

To give a guide a story should follow three acts and be within a set structure. There is a [url=https://youtu.be/TbFP7zGyfUs]video[/url] that you can watch that will explain it in greater detail, but the structure given is as follows:

[u][b]ACT 1[/b][/u]
[List][*]Introduction to character
[*]Introduction to setting
[*]The turning point
[/list]
[u][b]ACT 2[/b][/u]
[List][*]Sub Plot
[*]Love interest
[*]Midpoint
[*]Plan
[*]Execute
[/list]
[u][b]ACT 3[/b][/u]
[List][*]Failure
[*]Success
[/list]

Most of the time roleplays won't reach Act 3, but if you have a look at Act 1 and Act 2 you will notice something interesting...
- How many Roleplays start with a proper introduction of a character?
- How many Roleplays build up the setting for the characters?
- How many Roleplays have that important turning point that changes the character?

My answer, not many.

If you look closely most people will have this information in their character sheets and the OOC. They will skip over all these details and move on to Act 2. By page 2 of the IC I can guarantee that many roleplays will be planning the big battle, the player challenge, the love interest, and the many subplots... and yet these characters have failed to complete Act 1 properly. They don't know their other characters, they don't understand the world they live in, and they don't have that turning point [i](eg: "will you pick the blue or red pill?" ~ The Matrix)[/i]

So I bring up all this about pacing when we are talking about creativity because people can be too eager to just throw out half their hand of cards in the hopes of creating that cool, memorable character, only to find that they have less then a few "possible" ideas left. Ideas that can fall apart if the GM makes one simple, and harmless decision for the story. At that point you're only a handful pages into the roleplay and you realize it isn't working and you've lost your jam... hence writers block.

To sum it up, "Write less, and brainstorm more".

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[b]Edit:[/b] If you want a decent example you can look at one of the roleplays I'm in. I have the several sub plots per character (running 3 characters) and I can write so much at any point, but I drop in small hints every time with every post containing one piece of the overall puzzle. My other players know half of what I want to achieve but my audience isn't really them, it's the other characters in the roleplay. I want the other characters to figure out my character's story, and I want to read the reactions that have been carefully crafted and planned over a period of time.