Need Advice

Hello everyone . Seeing as I've been a part if fim for awhile now I figured I'd try to write a story for the site but I'm kinda if in a bind. I want to write a story like PussPuss's, Enigmatic Otaku, or Duelist96. All who have really inspired me with their work but as I said I'm stuck for a few reasons.

First, the characters. I want to do a human UN equestria like theirs but the two ponies I'm bot sure of. I either want to go with Derpy and Amethyst Star or a story with Berry Punch and another mare but i don't know who. I would appreciate any thoughts or suggestions.

Second, I've never wrote a clopfic ever. And I might need some advice.

So please to anyone out there who would be willing to help in any way I'd really appreciate it.