I play as a mage and this is what I do.
I get the double cast perk in destruction.
If a monster is using fire spells I use ice spells or if ice spells I use fire spells to attack. I use flames when they're using shock spells or summon a weapon before they empty my mana.
I put points in conjuration for when the monster casts silence I can cast a weapon spell. Plus I can fill soul gems with my casted weapon.
I always use ice spells on giants because I don't want them to run.
I only use electric spells as a last resort because I don't pick the perks to increase it's damage until I've filled other perks that I want. I get both levels of increase damage perks for fire and ice.
I use flames and frost spells a lot and only get 1 ranged fire spell for the soul caruin in dawnguard. If I want to use ranged spells I'll summon a ranged creature (they never miss their target). On conjuration I ignore the perks for summoned creatures and undead. I'll go up to adapt to cast summon bow and fill soul gems on the weapon.
I run backwards a lot but stay in battle mode until my spell points regen. I use anything in the area to duck behind and stay out of reach when ever possible. The best way to use the flames spell is with quick bursts. You want to catch them on fire.
I always carry a pickaxe for mining and when my mana runs out I have a weapon. I was able to get the mask that gives you 100% resistance to disease and poison at level 9 by using every trap in the dungeon against the creatures and closing gates behind me as I ran away waiting for my mana to regen. Got 2 nice ebony weapons too and I haven't started up dragons in my game yet.