Mage

Our frost spec focuses on keeping enemies at range, slowed and surviving while using mage’s massive mana pool on damaging spells. There are two ways of going about leveling frost mage. Single target spec is more focused on questing and killing 1-3 enemies at a time, opposite of that we have the original king of AoE grinding, pulling massive groups of mobs and mowing them down with blizzard.

General tips for both builds:

Keep your Arcane Intellect buffed along with your armor of choice.
Make sure your Conjure food and water are at the highest level possible and always make some in advance to ensure you never spend another gold on buying it from vendors.
Similarly to the previous tip, make your mana gem as an additional mana potion.
If you don’t intend to sell or use the cloth you get while leveling for tailoring, train your first aid. Bandages are a great way to lower your downtime.

AoE build

After reaching level 22 you will have 3/3 points in Improved Blizzard and you can start grinding with ease.

For AoE spec, make sure to get your Ice Armor up, and only use Molten Armor or Mage Armor if you can survive the pulls.
If you are out in the open world, get your Ice Barrier and/or Mana Shield going, mount up and start aggroing a pack of mobs you think you can manage. But do be careful, anything over 10 enemies and Blizzard‘s effectiveness starts going down.
If you are somewhere mounts aren’t available, use your wand attacks, Fire Blast, Ice Lance and body pull enemies as much as you are comfortable.
Here you can use Ice Block to group them up, if they already are, just use Frost Nova to root them in place. 
From here it’s just down to kiting them in one direction and slowing them down with Blizzard and Cone of Cold. If they get too close you can use Blink to get away after rooting them again with Frost Nova.
Finish off low health enemies with Arcane Explosion and Cone of Cold.
Make sure to keep yourself healthy with potions and Ice Barrier, and your mana high with Mana gems or Using Evocation for a few tics if mobs are frozen/slowed.

This method is great for long grinding sessions but can be used in many zones while leveling with quests that require you to kill a lot of enemies that have no ranged attacks. We found best results to be combining questing and grinding to not get bored easily.

Single target build

This build focuses on mana efficiency, and Frostbolt’s build-in slow to keep single enemies at bay and kill them before they manage to get close. For your armor of choice, use Molten Armor and keep your Ice Barrier when fighting ranged enemies to avoid pushback.

Use Frostbolt as your main damaging spell.
Use Icy Veins when available but make sure to think in advance if you will need your cooldown for more difficult enemies.
You can use Cold Snap to reset cooldown on your Icy Veins, Frost Nova or Ice Barrier when needed. This is your panic button for situations where something unexpected happens and you need more cc and/or a refresh on your Ice Barrier.
When Brain Freeze procs, cast an instant Fireball and later Frostfire Bolt.
Freeze mobs with Deep Freeze, if needed.
When Fingers of Frost procs, cast Frostbolt two times and right as you finish casting the second one spam Ice lance for it to benefit from the buff as well.

Your main focus when it comes to stats should be Intellect and stamina to increase your mana and health pool, to ensure you can survive initial pulls and have enough mana to continue casting.

Intellect > Stamina > Spirit > Crit

Water Elemental Freeze on cursor macro:
#showtooltip
/cast [@cursor] !Freeze

Ice block cancel/cast macro
#showtooltip
/cancelaura Ice Block
/cast Ice Block
/cqs

Major Glyphs:

Glyph of Evocation – is good for both unexpected situations and lower downtime if you decide to use it in between pulls.
Glyph of Frost Nova (AoE) or Glyph of Ice Lance (Single target)

Minor Glyphs:

Glyph of Frost Armor
Glyph of Arcane Intellect
Glyph of Slow Fall

Are all quality of life options