The info below is a bit out of date as it refers to the beta. If you happen to be looking for an up-to-date reference for your Dragonknight, I suggest this manual. It includes some killer advice on leveling up, builds, skill rotation, and gold farming.
One of the most crucial decisions you have to make when you are creating a character to use in the Elder Scrolls Online is choosing which class to play. This is important not only for your enjoyment of the game but also because as an MMO game, it will have an impact on your usefulness to other players.
While Elder Scrolls Online is not as strict as other MMOs in the same genre when it comes to weapon and armor selection, your freedom to select gear makes the special abilities of each class doubly important. Your future development as a player will be determined by your initial choice of which class to play. You may find yourself locked out of certain skill trees based on your decision.
The four classes to choose from are:
Dragon Knight
Templar
Sorcerer
Nightblade
The classes are just about evenly distributed in popularity, and there is a lot to like about each one. Templar is the most popular by a narrow margin and the Dragon Knight lags behind the others in terms of popularity. Which you choose will be heavily influences by the way you play the game.
Dragon Knight
You should play the Dragon Knight if you are looking for a tank. Tanking is a time-honored gaming tradition where one player runs forward to challenge opponents in melee combat while other characters perform actions from afar that do much more damage. The skill lines of the Dragon Knight lend itself well to this. Its Draconic Power skill line is basically tanking at a push of a button, making them very effective in melee combat. The Earthen Heart abilities will allow your Dragonknight to soak up a lot of damage, making this class the ideal tank.
Sorcerer
While tanking has its place in the game, it is not the only way to play. The closest that you are going to get to a buffer/debuffer in Elder Scrolls Online is the Sorcerer. Buffing and debuffing is a style of play where you make yourself or your allies more effective while your enemies are stripped of their effectiveness. Mage and Sorcerer types in MMOs are often like glass cannons that can deal a lot of damage but are very fragile, but the Sorcerer does not fall in that category. While your Storm Calling ability will deal massive damage, the Sorcerer also is very adept at self-buffing to match the requirements of close combat which is good to make eso gold. They also have some buffs that can add to the effectiveness of your allies. They are an exceptional debuffer, with their Dark Magic abilities cursing your enemies to mediocrity. In addition, Sorcerers can spam your opponents with summoned monsters who can tank for them while they are working their sabotage on enemy attributes.
Templar
The Templar is best used in a support position, as they have a vast array of skills that make them equally suited to keeping other classes on their feet. They are the only class that can heal, and this is an essential skill in the course of Elder Scrolls Online battles. Healing damage of your designated tank can make him basically immortal for as long as your spells hold out. This crucial role is what makes the Templar the most popular character choice.
Nightblade
The Nightblade is a wild-card type of character that can make a big impact on the success or failure of a battle. However, they are not well suited to tanking and not as valuable in support as Templars or Sorcerers. Where the Nightblade really excels is in sneaking around and attacking your enemies with lethal force. They may be weak and difficult to play at low levels but at high levels, their Assassination skills make them a must-have for any group. They are basically a character that can jump out of the shadows, tip the scale in a party’s favor, and disappear back in the darkness.
No matter which character class you choose, be careful to balance their abilities. Maxing out a particular skill or attribute may look good on paper but will have consequences down the line and lock you out of some of the most useful skills in the game.
The info above is a bit out of date as it refers to the beta. If you happen to be looking for an up-to-date reference for your Dragonknight, I suggest this walkthrough . It includes some killer advice on leveling up, builds, skill rotation, and gold farming.