I have a 32 level mage (PC, BASIC GAME). I'm finding it pretty darn difficult to kill some dragons. I play no armor.. I do ok if there are others so the dragon doesn't always focus on ME. One on one...its quite a challenge. Looking for any words of wisdom about how it might get easier at higher levels or tactics I may not have tried.

Thanks.

My mage is high in ILLUSION(80 )....... Destruction (45) ......Conjuration (55)

Impact.

That shouldn't be that difficult. Conjure an atronach and keep your distance. Take your time, when you're low on magicka and let it replenish. In a couple of levels, Phinis will offer the 2 atronach spelltomes you'll want to buy for the ultimate ranged and close-combat situations.
The key is to take your time and keep the distance between you and the dragon.

My mage is Lv. 65 now and the elder dragons often tear the summons apart, so a nice enchantment the speeds up magicka-regeneration comes in handy. I personally don't like too much reduction, and if I reduce the casting cost, it will always be the school of magic that my character is skilled in. (Altmer = illusion, Breton = conjuration, Dunmer = destruction)

Use the terrain to avoid getting hit, wards work like a charm as well, given you put some perks into restoration.

Use a sword. It isn't illegal to be a mage with a sword.

When you play with no armor...almose anything can kill you with mele.....dragons seem to be able to kill in one breath if you are exposed.

Followers and summoned Daedra definitely help. Between my Dremora Lord and Teldryn Sero (from Dragonborn), I barely have to lift a finger in combat.

Use summons to support and boost either spell absorbtion and/or spell resistance. That should help against their magic attacks. When they land, use your summons to help melee them.

Use cover. Look for a tree, a rock, a wall, or anything else you can jump behind. Never let it get close enough to chomp you or it's instant game over. Be careful about being too close even if you are behind something. I've had one go into the instant kill animation and get me right through a stone column because it was too close. Run if it lands if you have to. It's nothing to be ashamed of as unarmored mages are just too weak to stand toe to toe with them.

For damage conjure a bow if they're flying, or use a ranged destruction spell. Summon Dremora Lords, if you have that spell, for when it lands. The Lords will take the Dragon's focus away from you at all times until they die. When one dies summon another one so the dragon never focuses on you. If you don't have the Lords then summon your next most powerful tank. Keep using your ranged attacks whenever it comes near but stay close to cover in case it decides to pick on you for some reason. It shouldn't if you keep your conjured tanks up but just to be safe stay where it can't directly attack you. I don't like the Atronachs because even though they can do ranged damage they miss a lot and they are horrible at tanking when it comes in to attack. They also are not guaranteed to keep the dragon's attention the way conjured tanks will.

Just keep up your ranged damage when possible, keep your tanks up, and it'll go down in time. It just takes a bit of patience.