I loved 'Creepy Day Dream' but don't think much of the others at all. Rated that comic 'good' and your user 'Okay'. I say just keep reading the comics on the site, preferably in the 'top rated' section, and use ideas from there, and ideas from your past experiences in life, to write something funny.
Two golden rules:
1: Ignore the forumites for your first few months, 99.9% of all users' debut comics are shit, and the forumites will usually tell you this if you post your first few comics. I've written one-hundred and twenty-one comics so far, and i'll tell you now that the first eighty were truely shit
2: Quit with the dialogue boxes, they usually hinder the comic rather than help it.
3: Never trust Lima to be your accountant