[Manj]

Do you plan to get rank 1? If so, start working on Windmill as early as possible. In addition, if you plan to train other skills, do not train these following skills past:

Combat Mastery - B
Smash - 9
Critical Hit - 6
Ranged Mastery - A
Magic Mastery - B
Fireball - E
Thunder - E
Magnum Shot - 9
Defense - D

This is because starting Rank 4 Windmill, the requirements are intense and camping Tir Na Nog and fighting Zombies will be necessary. In order to be able to train your Windmill at Zombies, their strength has to be "Boss" level to you. If you train any of the above skills higher than the stated rank, then your power level will rise and Zombies will drop to "Awful" level long before you reach Rank 1 and that will make Windmill impossibly hard to train.