I'm here to help! Here are many very easy threads YOU can post in to get your 15 posts:

1. Post your pets: here
2. Post your Patronus: here
3. Post your unpopular opinion: here
4. Post what song you're listening to: here
5. Post the last TV show you watched: here
6. Post the last movie you watched: here
7. Post a series you've marathoned: here
8. Post your favorite Disney movie: here
9. Post the last game you played: here
10. Post a movie you're dying to see: here
11. Post how you found RPG-D: here
12. Post a "Welcome to RPG-D!" type comment on any number of these: here
13. Badly describe one of your characters: here
14. Post a favorite line from your last post: here
15. Post a favorite line from your buddy's last post (you can all just use me ;D): here
16. Post a new song you discovered this week: here
17. Post about a sandwich you enjoy: here
18. Post an irrational fear: here
19. Post about the origin of your username: here
20. Post a book recommendation: here