I'm having the hardest time determening how to enchant my armor. I'm a Mage .. my primary focus is Destruction and Conjuration.

Experiment! There are so many ways to play. So many things to do. Majicka regen? Health regen? There are so many possibilities.

I have limited supplies so I really don't want to experiment..

Enchanting for lower magicka cost for your favorite shcools is a very viable option, probably even more useful than increased magicka regen. And if I remember right, there's even an enchantment that bothe reduce the magicka cost for one chsool and boosts the amgicka regen i na single enchantmen.

If you can do dual enchants, pick that one for both your most used school anfd enjoy.