Alright here goes nothing! - - - -
Plot resetting:
~ Do not boot up your mayor first!
~ On a day you know there will be a new house plot.. Do not sign on as your Mayor.. If you do this the plot will be saved and you're screwed
~ Instead - Click on "New Save File" - create any name/looks for this character as he/she is only temporary (Unless you want to keep them)
~ Once you arrive in your town as your new character, wonder around and find the house plot
~ Is the house plot in a crappy place? Hit your home button and close the software - repeat the "New Save File" process
~ Is the house plot in a great place? Head over to the town hall and then to Nook's, place yourself a house, save - Then feel free to delete that character after you've saved.
^ Does that sound understandable? ^ Any questions I'm happy to answer for you, sometimes I'm not really great at explaining on the first try xD