Bring three potions with you. If there are someone doing it, or you know someone who is willing to help you, ask them. If it's still too hard, try adjusting your gear or go back and do some side quests to lvl up.
I have been defeated in the 2nd floor in the tower! Can I have an advice?
If you are too low of a level you will have many problems throughout Dragonspyre and beyond. You don't indicate what school you are either, so 'help' really can't be given, but you canplan ahead by seeing what lies on each floor:
It is a good idea to bring a friend ( I was lucky enough to find a new friend with the same quest as me ) and some potion bottles. There are a few health wisp floors (2nd and ?) to help you out. If you are death, things can be tricky, so bring a few prisms.