1. Go on to the next level: 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 50. 

2. Then the increase occurs every new 10 levels. 

3. You get 3 energy units when you land yourself a spouse.

4. Each child brings a permanent increase of 1 unit to your maximum energy.

5. Every time you buy Vodka (for gems), its "consumption" increases your maximum energy by 1 unit – permanently.