I didn't have any problem as a Mage and I was playing on the arguably harder ED.
Adding on to Trippy's list of tips:
5. Know when to use what spells. Like you said, you die quickly in closed areas. Cast Fireball. Burst damage and it has AE, which would outright kill most things, and if not that then get them in OHKO range for your weapon of choice. Another alternative is Magic Blast, but it's out damaged by Fireball and it doesn't have AE.
6. As for your magic damage being low, I assume you are trying to balance Spir/Int, which you shouldn't. If anything your Spir should be 50% of your Int. But I personally kept Spir at 1 and relied on equips to boost it. Once you get Int to 70 or 80, then pump Spir up. ^^; 60 - 70 is the magic number because of the FoV armor sets that increase Str/Dex/Int by 20.
7. As for you getting hit by other people, learning to dodge really helps. Backwards jumping gives you dodging while also letting more distance get between you and the enemy. The same could also be said for learning to use your environment, all of it prevents uneeded damage. If you can hide behind a rock, pop in and out, do so.
8. I guess my last tip would just to be sure you have the "best" equips for your lvl.
Goodluck!
