http://www.gamefaqs.com/3ds/997811-animal-crossing-new-leaf/faqs/65246
^ This guide is a great guide IMO. Scroll down (or ctrl+f) to "56) HAPPY HOME ACADEMY". It breaks down items by their point-value. So for example, something Gulliver or Katie gives you is innately worth more than some furniture from Timmy and Tommy. Also, refurbishing doesn't give you any extra points, but it can help unite your room in a colour theme (which can give you more points).
Also, try to get more exterior pieces that match the trendy theme, those help boost point value alot. Remember that your basement isn't counted so move all your trendy stuff out of there and shove it all in your other rooms.
Edit: Also, I just wanted to mention that you should also go catch cicadas and dump them on tables! They're worth 7777 points (since they're they're the lucky item in August). August is actually one of the easiest months to try to break the HHA 1.1 Million point barrier since there are so many lucky items.