Here are some tips into surviving fights with dragons without dying
Have at least 15K health
Eat some food such as Crusty Bread, which can easily be found in the inns located at the base camp of Cyrodiil
If you have a tank, it’s the best character to bring for Dragon fights as you will not have to heal much and can even taunt the Dragon (if it’s up to it).
Slot a self heal or shield
For magicka characters, slot your class-based healing ability or the shield from the Light Armor skill line
For stamina characters, use the Vigor skill from the Alliance skill line or the shield from the Undaunted skill line
For even better survival, slot a skill which grants Major Resolve. You can see here for the skills available to your class.
Potions are not sufficient when a dragon uses the “Soul Tear” ability which can do heavy damage overtime
If you have been putting equal points attribute points in the 3 attributes (Health, Magicka, Stamina) or wearing mixed armor (light/medium/heavy), now is a great time to reconsider.
A good PVE magicka build should wear at least 5pcs of light armor and most points in Magicka attribute. Likewise, a good stamina PVE build should wear 5pcs of medium armor and most points in Stamina attribute.
Avoid the front of the dragon
Unless you plan to tank it, you should stay at the sides or back
Do not go to the legs of the dragon too
When the dragon starts flying, keep off the centre of the arena before it does its one line of flame/frost. Keep off the flames it leaves behind as it can be a one shot death
And Block whenever the dragon whips its tail or lifts its wings depending on your position.
You only need to hit the dragon once to get loot
Yes, you only need to hit the dragon once and you are guaranteed to get loot.
Purely healing others will not grant you loot.