I'm a level 34 caster and I still haven't found boots or gloves that improve my casting ability. My boots give some shock resist and my gloves improve my unusable pickpocket skill. Are boots and gloves reserved for other strengths or am I just looking in the wrong places?
For gloves, the only usable magician boost you can enchant onto your gloves is a Magicka enchantment. For boots, there are no enchantments that are useful for casters. For a full list of possible enchantments, look here
This handy table is taken from the UESP:
As you can see, there is nothing to improve casting ability for the Arms or Feet slots. Magicka on your arms slot is one option, and I'd recommend the ever-useful "Fortify Carry Capacity" for your boots.