This is a work in progress. The actual character doesn't have all of the skills unlocked yet, so I don't have much info on how she'll do. So far (recently hit lv 50, about 400 CP), she's pretty hardy and does decent damage. She can hold up well in solo content, and seems to show some promise in group as a DPS.

As a magicka dragonknight, her main focus is on flame damage, with some emphasis on damage over time. You'll want to start with some ranged DOT abilities, and then move in to spam melee abilities.

Gear

Inferno staff on the back bar for ranged DOTs, and greatsword on the front bar for melee. Both should have a fire enchantment. Sharpened is probably best, but you might consider Charged to get a better chance of inflicting the burning status, or Infused on the greatsword to get more fire damage in your attacks.

The Heavy Weapons passive from the 2H line gives +6% general damage when using a greatsword, so it's the best physical weapon for a mag character. Critical Rush won't do much damage, being stamina based, but it gives us a much needed gap closer and reduces the target's speed (keeping them in our AoE radii longer).

Armor should be 5 light, 1 medium (legs), and 1 heavy (chest), to make use of the Undaunted passive, get a little extra stam regen to make sure Critical Rush is ready on demand, and get a little extra health. You don't lose too much magicka sustain this way, since Burning Embers, the main spammable, is very low-cost. Chest and legs can be infused, and the rest should be divines. They should all have a max magicka enchantment.

Jewelry should probably have a spell damage enchantment. Not sure what traits are best if you're using crafted jewelry.

So far I'm using 5 Law of Julianos and 5 War Maiden's. I plan to eventually use some fire-based monster set for the other 2, but for now I have two Mad Tinkerer's, to get a little extra crit.

Rotation

Before the fight, you can hit enemies with Elemental Drain (Weakness to Elements) if you're using it, and then buff with Molten Armaments and Flames of Oblivion. Then drop Scalding Rune to start the fight, and quickly follow with Cinder Storm. You can hit them with a Crushing Shock if they're casting; otherwise switch bars and use Critical Rush to jump in. Use Engulfing Flames once to make them weak to more fire damage. If you have Volatile Armor slotted, use it now. Then start weaving Burning Embers with light attacks. Refresh your DOTs and buffs as needed.

Food

Witchmother's Potent Brew is probably best. If you feel like you need more stamina, you could try a tri-stat food.