To favorite authors, just add them to the Favorite Authors list which is on the right when you click on My Mibba. Make sure to remember their exact username, punctuation and all, and they'll be saved there.
Also, to search a certain genre, you can go to Stories and then look on the right and there should be a breakdown of categories and genres.
1. Type in the search box at the Stories section. 2. You don't click on a rating scale thing like Quizilla. You can comment and subscribe to the story, which gives the story more stars. 3. Er. I suppose you can friend request them. Hope this helps some. =)