Hearthpwn

If u wanna save dust or just dislike Stargazer Luna put in Starcryer instead. If u face a lot of token decks, decks which floods the board or large minions, consider including Primordial Glyph instead of Magic Trick, which gives you a chance to get Blizzard, Flamestrike or other board clears options to deal with wide boards or Fireballs, for example, to deal with large minions. However just know Magic Trick is run because it allows the deck to go fast and Mage has amazing low-cost spells, which you potentially give up when including Primordial Glyph.

I dislike running Violet Spellwing, since Magic Missiles often ok at best and is beaten IMO by both Wand Thief and Wandmaker, since the first offer huge flexibility with its immediate discover-effect and better body being a 1/2, with its downside being activated by combo and Wandmakers often offering better and immediate spells, since mage has some of the best 1 mana spells in the game, with the downside of them being random and the card costing 2 mana. In both cases, you give up a 1-drop on turn 1, but since u are playing Quest mage turn one is reserved for Open the Waygate anyway, which alongside Violet Spellwing mediocre effect and body compared to the other options I take those to. Fell free to change one of each or two of one the alternatives to try out Violet Spellwing if you want.

Mulligan
Firstly keep the Quest in your starting hand, secondly the best cards to look for is either of your quest two-drops: Licensed Adventurer and Questing Explorer, thirdly I would look for any of your other 1 or 2 cost cards, excluding Evocation which is too random to depend on in the early game and you don't have the mana to fully utilizes its potential. You want to look for the best 1 or 2 cost cards which potentially can deal with or counter your opponent, for example, Demon hunters and Paladins are usually aggressive, so look for low cost cards to deal with their minions.