Shield equipped at all times while. When the battle starts I summon a creature or two and then whip out a Frost spell. I use this at long range and if I'm attacked at close range, I can pull out a Mace and go crazy.
Should I use a shield or just have Destruction/Conjuration in one hand and a Mace in the other?
Build:
http://www.ign.com/builds/the-elder-scrolls-5-skyrim/create?d=00000000000000000000000000000001111100000011111002000111100011000000020000000000000000000001000011111500010005110001100000000005011002