Wow! I and U are the hardest for ya? The hardest for me were always A and WO for some reason. XD I like U. My Japanese teacher, to help us memorize the characters, drew pictures using the characters, pictures of stuff that also had that sound in them. For instance, "U" turned into a person who was lifting something heavy and going "Oof!" XD And for "KA", she turned that character into a person practicing "KArate"! Stuff like that!
>_> To this day, those stupid little pictures still help me remember everything.
*pets Draco* No worries, I was stupid and it took me a while to learn them all. And as for katakana...>_> I still need to learn them all; I loved hiragana, but always hated katakana.