How to kill a dragon in Skyrim?

Solution 1:

I would say as Konerak said, get yourself a companion. I got one not that far in the game for free for becoming a thane of something something. And after that me and her killed a lot of dragons together. For some strange reason the dragons always focus more on companions then you. So mostly I stay next to it or behind it and fire arrows at it, while my companion tanks the damage. Doing some of the dark brotherhood quests you get a spell to summon an old ghostly assassin, that might help aswell.

But to do it just you vs a dragon I would say shout a lot and remember the 5 D's : Dodge, Duck, Dip, Dive and Dodge!

Solution 2:

the key for dragon slaying is a reliable way to have knockback. Unrelenting force thu'um, the impact perk(destruction) or any other way.

I find that mana regen and health regen items help, any resistance potions related to the dragons breath, any enchanted armor with that resistance would help as well.

always look for cover, as breath attacks will bring you down really fast.

Get a companion that uses ranged attacks(there is a mage in riften that costs 500g, he is pretty good for this). In all, fight smart and dont take any damage that you dont need to