A while ago, I got to Celestia. I'm level 52 in the Survey Camp. The enemies are too tough for me. Do you have any suggestions about how Celestia will be easier for me?
Exactly what fusionsun said! Crafted gear from Wintertusk helps a lot to ease your way through Celestia and once you reach Zafaria do the waterworks dungeon and farm waterworks gear. Waterworks gear is the best gear in the game up until Hades but I just skipped Tartarus and went straight to Darkmoor gear. But honestly, Celestia is easy as. You shouldn't be having any trouble with it. If you're finding it difficult just find a questing buddy!
If you can, you should do Wintertusk before Celestia. Not only do you get massive amounts of XP, you can craft some awesome L56 gear. The recipes are at the Sudrilund vendor. By the time you finish Wintertusk, you will be several levels higher, have some nice gear and you'll be able to do Celestia pretty easily.
In the meantime, there are some L50 vendors at the beginning of Wintertusk that can provide some 'temporary' gear to help you out.
I am also having problems with Celestia, and Wintertusk...to get in I have to defeat a bunch of monsters that are resistant to fire, so I can't even get in the gate.
I'm balance so it's pretty difficult since I don't have the luxury of buffing my wizard up without any real opposition anymore. I had to completely overhaul my strategy when fighting everything: bosses to mobs. I'd suggest you find gear that better suits your wizard for Celestia or practice optimizing your strategy a bit.