Two of your gigs are in legally ambiguous areas (do homework, write “glowing” review), so you may want to be prepared to see them deleted by Fiverr in the event they receive complaints.
The forums, especially “Tips” and “FAQ”, have hundreds of good posts, some being permanent, closed threads, offering tips, suggestions and shared experiences, all to help new members succeed on Fiverr. I suggest you continue to browse through them, as they will answer many of your questions. For those more personal questions that you have, you must realize that the answers are going to vary wildly: some people have 1 gig, some have 20. Some categories have much competition and therefore fewer sales for newcomers.
Good luck, and enjoy your summer~