"You will find Yazzashah, that up to level 31, you DO NOT want to level fast. Reason is that you need sp to get your general and special skills. You will be glad to get sp now then later when it is REALLY hard. But you do not learn this till someone tells you or when you make level 50 and trying to sp farm.

Here is short list
Level 11 - Elite Goblin [Dratan] 1925
Level 12 - Sasquatch [Juno] 1925
Level 13 - Larva [Dratan]1650
Level 14 - Larva [Dratan]1485
Level 15 - Little Treant [Juno] 1650, Sasquatch [Juno] 1347
Level 16 - Horn Beast [Juno] 1485, Little Treant [Juno] 1485
Level 17 - Little Treant [Juno] 1320
Level 18 - Drake 1375 [Juno]
Level 19 - Horn Beast 1155 [Juno]
Level 20 - Drake 1100 [Juno], Harpy 1100 [Dratan], Skeleton Soldier 1045
[Velpist temple - Juno]

The drakes you should level up to level 23. Read in the strategy guide now and it will explain now. Also the trick is to always level on the monster BELOW you. This has mostly to do with getting sp. What you do is to time yourself for 15 minutes and find out how much sp/xp you get from a monster above you and a monster below you. You will find that the lower monsters you get more cuz you kill faster and they can not hit you much so you do not have to recover. Also the lower monsters are hard to kill you too, cuz if you die, you lose xp and playing time. "