yeah just a short while ago I did went through and got all the elixirs, costumes and elemental fruit. The costumes and elixirs were pretty easy to see what I'd done and what I hadn't yet done but the fruit was a bastard...
basically I took MysticWeirdo's guide and cut/past the fruit into a new text file, then I manually sorted it by area, so I put all the magic kingdom stuff in one list and the forgotten forrest glade stuff in another list...
then I went through each area until I had looked in every location. If a sign quest is completed the sign will have disappeared, if a flower has been used then you should see a circle with dirt in it on the ground where it was, quests usually leave someone you can talk to who will thank you for having completed the quest. Any sort of chest or pot you have to break simply wont be there. The hardest part was understanding MysticWeirdo's descriptions, he easily had 5 different names for what should be the "Forgotten Forrest Glade" other then that it's just time consuming.