Experiance Gain:

Eech time you play unranked, versus ai or ranked you will earn experience for your account and the hero you're playing.
If you play team league the experience rewards are much higher than in other game modes.

Bellow are the rewards you will earn upon reaching your hots account or hero level.

Hots Account Rewards:

Level 2: 1,000 gold
Level 4: 1,000 gold
Level 5: Hero Rotation Slot
Level 6: Daily Quests unlocked
Level 7: Hero Rotation Slot
Level 8: 2,000 gold
Level 10: 2,000 gold
Level 10: 7day stimpack (+100% exp and 150% gold gain)
Level 12: Hero Rotation Slot
Level 15: Hero Rotation Slot
Level 20: 2,000 gold
Level 25: 2,000 gold
Level 30: 2,000 gold
Level 35: 2,000 gold
Level 40: 2,000 gold

Hots Hero Rewards:

Level 5: 500 gold
Level 6: Mount variation
Level 6: Hero Portrait
Level 7: Skin variation
Level 8: Skin variation
Level 9: Hero master portrait
Level 9: Mount variation
Level 9: 750 gold
Level 10: Master skin (you can buy it for 10000gold it has 2 variations wich are unlocked at level 10)
Level 15: 1,000 gold
Level 20: 2,000 gold

Skin Variations:

At levels 7 and 8, you’ll unlock Skin variations.Each Skin you own (including a Hero’s base model) offers three different options for customizing the look of your Hero in-game.

Mount Variations:

Mount variations will unlock at Hero levels 6 and 9. Much like Skin variations, Mount variations allow you to customize the steeds.

Dont forget if you dont have time to the level up Gramno is here for you http://www.gramno.com/hots-hero-leveling