Next answer: the practice dummy. You just gotta do whatever move it Is right a few times and he'll be satisfied.
With the dungeon door it's tricky. Two of them will pull(in the correct order) but then you have to pull one of those two again before pullin the third one. Then pull the main door one (sorry. Don't remember the order.
In the sewers you gotta have your timing right. Make sure if you go in the water it's when the water moves down. There are also quite a few of the hooks for the rope gun you have. Use those as well
The dragon skeleton: equip a nova/supernova mote to all of your stuff. When he breaths ice or fire, put your Shield up(be tor) then when he's a head, use Roberta's magic to finish it off.
The rope gun: find the hook type things, point your little red(aim) thing at it and it should turn green. Press R2
The plague snake(in bogshot swamp). Jump on the higher blocks. Wait till its about to attack, then block. Don't hold your shield up, he'll start spewing poison gas. When you block it's attacks, it'll be stunned. Use that time to attack. (I preferred the jump attack myself). Will take a while, but easiest way to beat it.
I hope I answered these questions well(previous post was mine too) I know my post is later the your questions but if you're newly stuck or still stuck then here are some awesome Neopets Darkest Faerie answers!!